{ "document": { "category": "csaf_base", "csaf_version": "2.0", "distribution": { "tlp": { "label": "WHITE" } }, "lang": "en", "notes": [ { "category": "legal_disclaimer", "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings." } ], "publisher": { "category": "coordinator", "contact_details": "cert@ncsc.nl", "name": "National Cyber Security Centre", "namespace": "https://www.ncsc.nl/" }, "title": "CVE-2026-21509", "tracking": { "current_release_date": "2026-08-03T17:31:00.532450Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-21509", "initial_release_date": "2026-01-26T17:39:39.728298Z", "revision_history": [ { "date": "2026-01-26T17:39:39.728298Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (5).| References created (1).| CWES updated (1)." }, { "date": "2026-01-26T17:39:45.335412Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-01-26T18:19:44.740742Z", "number": "3", "summary": "Source connected.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (10).| Product Threats created (20).| Product Remediations created (6).| CWES updated (1).| Exploitable created." }, { "date": "2026-01-26T18:19:48.653318Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-01-26T18:26:48.804775Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (1).| CWES updated (1)." }, { "date": "2026-01-26T18:26:52.839495Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-01-26T19:04:40.092454Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| News created (1)." }, { "date": "2026-01-26T19:04:42.755829Z", "number": "8", "summary": "NCSC Score updated." }, { "date": "2026-01-26T19:39:42.687952Z", "number": "9", "summary": "CVSS updated.| Unknown change." }, { "date": "2026-01-26T21:07:53.529617Z", "number": "10", "summary": "Source connected.| CVE status created. (valid)| Description created for source.| Products connected (1).| Exploits created (1).| References created (1).| CWES updated (1)." }, { "date": "2026-01-26T21:08:00.277366Z", "number": "11", "summary": "NCSC Score updated." }, { "date": "2026-01-26T21:26:47.438579Z", "number": "12", "summary": "References created (1)." }, { "date": "2026-01-26T21:39:23.753335Z", "number": "13", "summary": "References created (1).| Unknown change." }, { "date": "2026-01-26T23:39:02.191897Z", "number": "14", "summary": "Products connected (1).| Products created (1).| Products removed (2)." }, { "date": "2026-01-27T02:39:27.873565Z", "number": "15", "summary": "Products created (1).| Products removed (1)." }, { "date": "2026-01-27T03:41:38.237275Z", "number": "16", "summary": "Source created.| CVE status created. (valid)" }, { "date": "2026-01-27T05:39:00.684378Z", "number": "17", "summary": "Unknown change." }, { "date": "2026-01-27T07:28:04.483564Z", "number": "18", "summary": "Source connected.| CVE status created. (valid)" }, { "date": "2026-01-27T09:29:47.752212Z", "number": "19", "summary": "Source created.| CVE status created. (valid)| News created (1)." }, { "date": "2026-01-27T09:29:55.053711Z", "number": "20", "summary": "NCSC Score updated." }, { "date": "2026-01-27T09:34:50.078846Z", "number": "21", "summary": "Source created.| CVE status created. (valid)| News created (1)." }, { "date": "2026-01-27T09:34:58.916489Z", "number": "22", "summary": "NCSC Score updated." }, { "date": "2026-01-27T10:06:37.950181Z", "number": "23", "summary": "Source created.| CVE status created. (valid)| Products created (4).| Product Identifiers created (5).| Products connected (1).| References created (4)." }, { "date": "2026-01-27T10:06:40.703952Z", "number": "24", "summary": "NCSC Score updated." }, { "date": "2026-01-27T13:15:51.227657Z", "number": "25", "summary": "NCSC Score updated." }, { "date": "2026-01-27T14:39:04.241612Z", "number": "26", "summary": "Source created.| CVE status created. (valid)| EPSS created." }, { "date": "2026-01-27T14:39:06.656004Z", "number": "27", "summary": "Unknown change." }, { "date": "2026-01-27T14:39:06.806884Z", "number": "28", "summary": "NCSC Score updated." }, { "date": "2026-01-27T15:18:17.653336Z", "number": "29", "summary": "NCSC Score updated." }, { "date": "2026-01-27T16:07:46.695709Z", "number": "30", "summary": "Description removed for source.| Description created for source." }, { "date": "2026-01-27T16:26:48.774892Z", "number": "31", "summary": "Products connected (5).| Product Identifiers created (10).| Product Identifiers removed (5)." }, { "date": "2026-01-27T16:26:52.211318Z", "number": "32", "summary": "NCSC Score updated." }, { "date": "2026-01-28T00:19:58.802722Z", "number": "33", "summary": "CVSS updated.| Product Threats created (10).| Product Threats removed (10).| Product Remediations created (4)." }, { "date": "2026-01-28T12:19:03.815403Z", "number": "34", "summary": "NCSC Score updated." }, { "date": "2026-01-28T14:18:18.539231Z", "number": "35", "summary": "NCSC Score updated." }, { "date": "2026-01-28T21:17:34.108127Z", "number": "36", "summary": "NCSC Score updated." }, { "date": "2026-01-29T14:14:27.392913Z", "number": "37", "summary": "EPSS updated." }, { "date": "2026-01-29T14:14:28.715593Z", "number": "38", "summary": "NCSC Score updated." }, { "date": "2026-01-30T13:19:09.135010Z", "number": "39", "summary": "NCSC Score updated." }, { "date": "2026-01-30T14:24:37.151693Z", "number": "40", "summary": "EPSS updated." }, { "date": "2026-01-30T14:24:49.481408Z", "number": "41", "summary": "NCSC Score updated." }, { "date": "2026-02-01T17:28:00.287505Z", "number": "42", "summary": "NCSC Score updated." }, { "date": "2026-02-02T12:17:52.242154Z", "number": "43", "summary": "NCSC Score updated." }, { "date": "2026-02-02T21:04:45.255071Z", "number": "44", "summary": "Source created.| CVE status created. (valid)| News created (1)." }, { "date": "2026-02-02T21:04:52.848533Z", "number": "45", "summary": "NCSC Score updated." }, { "date": "2026-02-03T11:30:39.545229Z", "number": "46", "summary": "Source created.| CVE status created. (valid)| News created (1)." }, { "date": "2026-02-03T11:30:48.802382Z", "number": "47", "summary": "NCSC Score updated." }, { "date": "2026-02-03T17:17:39.000737Z", "number": "48", "summary": "NCSC Score updated." }, { "date": "2026-02-03T19:17:58.647079Z", "number": "49", "summary": "NCSC Score updated." }, { "date": "2026-02-05T12:17:51.688666Z", "number": "50", "summary": "NCSC Score updated." }, { "date": "2026-02-05T20:18:02.755785Z", "number": "51", "summary": "NCSC Score updated." }, { "date": "2026-02-06T12:33:55.325271Z", "number": "52", "summary": "NCSC Score updated." }, { "date": "2026-02-10T15:25:18.289533Z", "number": "53", "summary": "Product Identifiers created (10).| Product Identifiers removed (10).| References created (2)." }, { "date": "2026-02-10T15:25:25.745546Z", "number": "54", "summary": "NCSC Score updated." }, { "date": "2026-02-10T15:38:52.484411Z", "number": "55", "summary": "References created (2)." }, { "date": "2026-02-11T14:14:16.849588Z", "number": "56", "summary": "EPSS updated." }, { "date": "2026-02-12T12:21:22.139360Z", "number": "57", "summary": "NCSC Score updated." }, { "date": "2026-02-12T14:15:00.511954Z", "number": "58", "summary": "EPSS updated." }, { "date": "2026-02-13T14:13:12.994909Z", "number": "59", "summary": "EPSS updated." }, { "date": "2026-02-13T14:13:21.518571Z", "number": "60", "summary": "NCSC Score updated." }, { "date": "2026-02-16T14:13:25.871538Z", "number": "61", "summary": "EPSS updated." }, { "date": "2026-02-16T14:13:31.773174Z", "number": "62", "summary": "NCSC Score updated." }, { "date": "2026-02-17T14:13:00.632379Z", "number": "63", "summary": "EPSS updated." }, { "date": "2026-02-17T14:13:12.387416Z", "number": "64", "summary": "NCSC Score updated." }, { "date": "2026-02-18T15:06:29.738306Z", "number": "65", "summary": "EPSS updated." }, { "date": "2026-02-18T15:06:36.564891Z", "number": "66", "summary": "NCSC Score updated." }, { "date": "2026-02-19T18:27:45.974089Z", "number": "67", "summary": "NCSC Score updated." }, { "date": "2026-02-27T14:38:15.890153Z", "number": "68", "summary": "EPSS updated." }, { "date": "2026-02-27T14:38:18.017323Z", "number": "69", "summary": "NCSC Score updated." }, { "date": "2026-03-03T23:05:57.563710Z", "number": "70", "summary": "EPSS updated." }, { "date": "2026-03-03T23:06:07.313667Z", "number": "71", "summary": "NCSC Score updated." }, { "date": "2026-03-09T14:42:19.336435Z", "number": "72", "summary": "EPSS updated." }, { "date": "2026-03-09T14:42:21.839379Z", "number": "73", "summary": "NCSC Score updated." }, { "date": "2026-03-10T11:04:49.760075Z", "number": "74", "summary": "Source created.| CVE status created. (valid)| News created (1)." }, { "date": "2026-03-13T12:20:16.333490Z", "number": "75", "summary": "NCSC Score updated." }, { "date": "2026-03-19T18:40:41.682003Z", "number": "76", "summary": "Source connected.| CVE status created. (valid)| Description created for source.| Products connected (1).| Exploits created (1).| References created (1).| CWES updated (1)." }, { "date": "2026-03-19T18:40:44.273337Z", "number": "77", "summary": "NCSC Score updated." }, { "date": "2026-03-20T10:03:51.179556Z", "number": "78", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-20T19:17:44.211517Z", "number": "79", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (5).| Product Identifiers created (5).| References created (4).| CWES updated (1)." }, { "date": "2026-03-20T19:17:47.311041Z", "number": "80", "summary": "NCSC Score updated." }, { "date": "2026-03-21T15:49:26.420304Z", "number": "81", "summary": "EPSS updated." }, { "date": "2026-03-22T15:36:52.641572Z", "number": "82", "summary": "EPSS updated." }, { "date": "2026-03-22T15:36:56.602072Z", "number": "83", "summary": "NCSC Score updated." }, { "date": "2026-03-26T12:18:15.269467Z", "number": "84", "summary": "NCSC Score updated." }, { "date": "2026-04-01T14:40:49.732625Z", "number": "85", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (5).| References created (4).| CWES updated (1).| Unknown change." }, { "date": "2026-04-01T14:40:52.234274Z", "number": "86", "summary": "NCSC Score updated." }, { "date": "2026-04-04T18:20:58.996642Z", "number": "87", "summary": "EPSS updated." }, { "date": "2026-04-04T18:21:04.083604Z", "number": "88", "summary": "NCSC Score updated." }, { "date": "2026-04-05T15:56:20.623527Z", "number": "89", "summary": "NCSC Score updated." }, { "date": "2026-04-10T16:06:01.658127Z", "number": "90", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-04-10T16:06:05.483591Z", "number": "91", "summary": "NCSC Score updated." }, { "date": "2026-04-21T15:07:31.635236Z", "number": "92", "summary": "EPSS updated." }, { "date": "2026-04-21T15:07:35.521402Z", "number": "93", "summary": "NCSC Score updated." }, { "date": "2026-05-07T15:05:38.400049Z", "number": "94", "summary": "EPSS updated." }, { "date": "2026-05-07T15:05:40.205915Z", "number": "95", "summary": "NCSC Score updated." }, { "date": "2026-05-20T15:38:05.463607Z", "number": "96", "summary": "EPSS updated." }, { "date": "2026-05-20T15:38:15.260576Z", "number": "97", "summary": "NCSC Score updated." }, { "date": "2026-05-22T16:04:52.020328Z", "number": "98", "summary": "EPSS updated." }, { "date": "2026-05-22T16:04:59.084643Z", "number": "99", "summary": "NCSC Score updated." }, { "date": "2026-05-22T19:18:48.107284Z", "number": "100", "summary": "NCSC Score updated." }, { "date": "2026-05-28T16:26:58.438850Z", "number": "101", "summary": "EPSS updated." }, { "date": "2026-05-28T16:27:00.269361Z", "number": "102", "summary": "NCSC Score updated." }, { "date": "2026-05-29T17:31:33.898302Z", "number": "103", "summary": "EPSS updated." }, { "date": "2026-05-29T17:31:41.838182Z", "number": "104", "summary": "NCSC Score updated." }, { "date": "2026-06-02T14:52:39.823314Z", "number": "105", "summary": "EPSS updated." }, { "date": "2026-06-02T14:52:50.963110Z", "number": "106", "summary": "NCSC Score updated." }, { "date": "2026-06-03T03:29:21.375079Z", "number": "107", "summary": "NCSC Score updated." }, { "date": "2026-06-03T15:34:33.846448Z", "number": "108", "summary": "EPSS updated." }, { "date": "2026-06-03T15:34:36.236487Z", "number": "109", "summary": "NCSC Score updated." }, { "date": "2026-06-06T16:10:38.668169Z", "number": "110", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-06-06T16:10:41.240083Z", "number": "111", "summary": "NCSC Score updated." }, { "date": "2026-06-11T15:01:13.188287Z", "number": "112", "summary": "EPSS updated." }, { "date": "2026-06-11T15:01:15.348279Z", "number": "113", "summary": "NCSC Score updated." }, { "date": "2026-06-15T17:49:24.127907Z", "number": "114", "summary": "EPSS updated." }, { "date": "2026-06-15T17:49:25.659828Z", "number": "115", "summary": "NCSC Score updated." }, { "date": "2026-06-28T00:47:32.624246Z", "number": "116", "summary": "Source connected.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (5).| Exploits created (1).| References created (1).| Exploitable created." }, { "date": "2026-06-28T00:47:43.137094Z", "number": "117", "summary": "NCSC Score updated." }, { "date": "2026-07-01T16:18:26.384444Z", "number": "118", "summary": "NCSC Score updated." }, { "date": "2026-07-06T04:30:28.133961Z", "number": "119", "summary": "NCSC Score updated." }, { "date": "2026-07-09T21:20:35.357052Z", "number": "120", "summary": "NCSC Score updated." }, { "date": "2026-07-24T15:22:28.978205Z", "number": "121", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-07-24T15:22:51.026465Z", "number": "122", "summary": "NCSC Score updated." }, { "date": "2026-08-03T13:15:52.785714Z", "number": "123", "summary": "NCSC Score updated." } ], "status": "interim", "version": "123" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/unknown", "product": { "name": "vers:unknown/unknown", "product_id": "CSAFPID-2043301", "product_identification_helper": { "cpe": "cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*" } } } ], "category": "product_name", "name": "365_apps" }, { "branches": [ { "category": "product_version_range", "name": "vers:unknown/unknown", "product": { "name": "vers:unknown/unknown", "product_id": "CSAFPID-1430029", "product_identification_helper": { "cpe": "cpe:/a:microsoft:365_apps:-" } } } ], "category": "product_name", "name": "Microsoft 365 Apps" }, { "branches": [ { "category": "product_version_range", "name": "vers:unknown/16.0.1|Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.

\n", "title": "microsoft - https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-Jan" }, { "category": "description", "text": "Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.", "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-21509" }, { "category": "description", "text": "Microsoft Office contains a security feature bypass vulnerability in which reliance on untrusted inputs in a security decision in Microsoft Office could allow an unauthorized attacker to bypass a security feature locally. Some of the impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.\nApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.", "title": "cisagov - https://www.cisa.gov/known-exploited-vulnerabilities-catalog" }, { "category": "description", "text": "Microsoft Office contains a security feature bypass vulnerability in which reliance on untrusted inputs in a security decision in Microsoft Office could allow an unauthorized attacker to bypass a security feature locally. Some of the impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.\nApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.", "title": "cisagov - https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json" }, { "category": "description", "text": "Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-21509" }, { "category": "description", "text": "Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/21xxx/CVE-2026-21509.json" }, { "category": "description", "text": "Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.", "title": "euvdkev - https://euvdservices.enisa.europa.eu/api/search?fromScore=0&toScore=10&fromEpss=0&toEpss=100&exploited=true&page=0&size=50" }, { "category": "other", "text": "0.72152", "title": "EPSS" }, { "category": "other", "text": "8.1", "title": "NCSC Score" }, { "category": "other", "text": "Is related to (a version of) an uncommon product, There is news data available from source Bleepingcomputer, VENDOR FIX as product remediation category, There is product data available from source Certbundde, There is cvss data available from a private source, The value of the most recent EPSS score, There is product data available from a private source", "title": "NCSC Score top increasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-1288319", "CSAFPID-1288369", "CSAFPID-3105172", "CSAFPID-5137204", "CSAFPID-5137205", "CSAFPID-5137206", "CSAFPID-5137207", "CSAFPID-5137209", "CSAFPID-5137210", "CSAFPID-5137211", "CSAFPID-5137212", "CSAFPID-5137216", "CSAFPID-5137217", "CSAFPID-1332282", "CSAFPID-5466228", "CSAFPID-5467387", "CSAFPID-1430029", "CSAFPID-5467987", "CSAFPID-5467988", "CSAFPID-5467989", "CSAFPID-5467990", "CSAFPID-2001224", "CSAFPID-2001227", "CSAFPID-2043301", "CSAFPID-2062421", "CSAFPID-2551570", "CSAFPID-1430023", "CSAFPID-1430028", "CSAFPID-8023744", "CSAFPID-8023745", "CSAFPID-8023746" ] }, "references": [ { "category": "external", "summary": "Source - cveprojectv5", "url": "https://www.cve.org/CVERecord?id=CVE-2026-21509" }, { "category": "external", "summary": "Source - microsoft", "url": "https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-Jan" }, { "category": "external", "summary": "Source - nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21509" }, { "category": "external", "summary": "Source - bleepingcomputer", "url": "https://www.bleepingcomputer.com/news/microsoft/microsoft-patches-actively-exploited-office-zero-day-vulnerability/" }, { "category": "external", "summary": "Source - cisagov", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog" }, { "category": "external", "summary": "Source - hkcert", "url": "https://www.hkcert.org/security-bulletin/microsoft-office-security-restriction-bypass-vulnerability_20260127" }, { "category": "external", "summary": "Source - ncscclear", "url": "https://advisories.ncsc.nl/advisory?id=NCSC-2026-0039" }, { "category": "external", "summary": "Source - securitynl", "url": "https://www.security.nl/posting/922272/Microsoft+rolt+noodpatch+uit+voor+actief+aangevallen+kwetsbaarheid+in+Office?channel=rss" }, { "category": "external", "summary": "Source - securityweek", "url": "https://www.securityweek.com/microsoft-patches-office-zero-day-likely-exploited-in-targeted-attacks/" }, { "category": "external", "summary": "Source - certbundde", "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0221.json" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-21509" }, { "category": "external", "summary": "Source - bleepingcomputer", "url": "https://www.bleepingcomputer.com/news/security/russian-hackers-exploit-recently-patched-microsoft-office-bug-in-attacks/" }, { "category": "external", "summary": "Source - securityweek", "url": "https://www.securityweek.com/russias-apt28-rapidly-weaponizes-newly-patched-office-vulnerability/" }, { "category": "external", "summary": "Source - bleepingcomputer", "url": "https://www.bleepingcomputer.com/news/security/apt28-hackers-deploy-customized-variant-of-covenant-open-source-tool/" }, { "category": "external", "summary": "Source - cisagov", "url": "https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-21509" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/21xxx/CVE-2026-21509.json" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=10000" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=20000" }, { "category": "external", "summary": "Source - euvdkev", "url": "https://euvdservices.enisa.europa.eu/api/search?fromScore=0&toScore=10&fromEpss=0&toEpss=100&exploited=true&page=0&size=50" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=30000" }, { "category": "external", "summary": "News - bleepingcomputer", "url": "https://www.bleepingcomputer.com/news/microsoft/microsoft-patches-actively-exploited-office-zero-day-vulnerability/" }, { "category": "external", "summary": "News - securitynl", "url": "https://www.security.nl/posting/922272/Microsoft+rolt+noodpatch+uit+voor+actief+aangevallen+kwetsbaarheid+in+Office?channel=rss" }, { "category": "external", "summary": "News - securityweek", "url": "https://www.securityweek.com/microsoft-patches-office-zero-day-likely-exploited-in-targeted-attacks/" }, { "category": "external", "summary": "News - bleepingcomputer", "url": "https://www.bleepingcomputer.com/news/security/russian-hackers-exploit-recently-patched-microsoft-office-bug-in-attacks/" }, { "category": "external", "summary": "News - securityweek", "url": "https://www.securityweek.com/russias-apt28-rapidly-weaponizes-newly-patched-office-vulnerability/" }, { "category": "external", "summary": "News - bleepingcomputer", "url": "https://www.bleepingcomputer.com/news/security/apt28-hackers-deploy-customized-variant-of-covenant-open-source-tool/" }, { "category": "external", "summary": "Reference - certbundde; cveprojectv5; euvdkev; nvd", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21509" }, { "category": "external", "summary": "Reference - cisagov", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21509" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21509" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0221.json" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-0221" }, { "category": "external", "summary": "Reference - certbundde", "url": "https://github.com/advisories/GHSA-ch84-h92g-mw93" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://www.vicarius.io/vsociety/posts/cve-2026-21509-detection-script-microsoft-office-security-feature-bypass-vulnerability" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://www.vicarius.io/vsociety/posts/cve-2026-21509-mitigation-script-microsoft-office-security-feature-bypass-vulnerability" } ], "remediations": [ { "category": "vendor_fix", "details": "Click to Run", "product_ids": [ "CSAFPID-5137206", "CSAFPID-5137207", "CSAFPID-5137209", "CSAFPID-5137210", "CSAFPID-5137211", "CSAFPID-5137212", "CSAFPID-5137204", "CSAFPID-5137205" ] }, { "category": "vendor_fix", "details": "5002713", "product_ids": [ "CSAFPID-5137216", "CSAFPID-5137217" ], "url": "https://www.microsoft.com/en-us/download/details.aspx?id=108535" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C", "baseScore": 7.8, "baseSeverity": "HIGH" }, "products": [ "CSAFPID-1288319", "CSAFPID-1288369", "CSAFPID-1332282", "CSAFPID-1430023", "CSAFPID-1430028", "CSAFPID-1430029", "CSAFPID-2001224", "CSAFPID-2001227", "CSAFPID-2043301", "CSAFPID-2062421", "CSAFPID-2551570", "CSAFPID-3105172", "CSAFPID-5137204", "CSAFPID-5137205", "CSAFPID-5137206", "CSAFPID-5137207", "CSAFPID-5137209", "CSAFPID-5137210", "CSAFPID-5137211", "CSAFPID-5137212", "CSAFPID-5137216", "CSAFPID-5137217", "CSAFPID-5466228", "CSAFPID-5467387", "CSAFPID-5467987", "CSAFPID-5467988", "CSAFPID-5467989", "CSAFPID-5467990", "CSAFPID-8023744", "CSAFPID-8023745", "CSAFPID-8023746" ] } ], "threats": [ { "category": "impact", "details": "Security Feature Bypass", "product_ids": [ "CSAFPID-5137204", "CSAFPID-5137205", "CSAFPID-5137206", "CSAFPID-5137207", "CSAFPID-5137209", "CSAFPID-5137210", "CSAFPID-5137211", "CSAFPID-5137212", "CSAFPID-5137216", "CSAFPID-5137217" ] }, { "category": "exploit_status", "details": "Publicly Disclosed:No;Exploited:Yes;Latest Software Release:Exploitation Detected", "product_ids": [ "CSAFPID-5137204", "CSAFPID-5137205", "CSAFPID-5137206", "CSAFPID-5137207", "CSAFPID-5137209", "CSAFPID-5137210", "CSAFPID-5137211", "CSAFPID-5137212", "CSAFPID-5137216", "CSAFPID-5137217" ] }, { "category": "exploit_status", "details": "exploited" } ], "title": "CVE-2026-21509" } ] }