{ "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-2026-31834", "tracking": { "current_release_date": "2026-03-23T01:36:52.128740Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-31834", "initial_release_date": "2026-03-10T22:26:22.124244Z", "revision_history": [ { "date": "2026-03-10T22:26:22.124244Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (1).| CWES updated (1)." }, { "date": "2026-03-10T22:26:26.267033Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-03-10T22:38:39.046915Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (2).| References created (1).| CWES updated (1)." }, { "date": "2026-03-10T22:38:40.467478Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-03-11T14:54:31.448826Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-11T14:54:44.174531Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-03-11T15:52:36.752255Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)." }, { "date": "2026-03-11T15:52:41.964218Z", "number": "8", "summary": "NCSC Score updated." }, { "date": "2026-03-11T16:39:54.432019Z", "number": "9", "summary": "Unknown change." }, { "date": "2026-03-18T20:25:29.333344Z", "number": "10", "summary": "Products created (1).| Product Identifiers created (2).| Products connected (1)." }, { "date": "2026-03-18T20:25:31.784392Z", "number": "11", "summary": "NCSC Score updated." }, { "date": "2026-03-19T15:30:43.236518Z", "number": "12", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)." }, { "date": "2026-03-20T09:32:43.805745Z", "number": "13", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-20T09:32:46.700269Z", "number": "14", "summary": "NCSC Score updated." } ], "status": "interim", "version": "14" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/>=15.3.1|<16.5.1", "product": { "name": "vers:unknown/>=15.3.1|<16.5.1", "product_id": "CSAFPID-5779780" } }, { "category": "product_version_range", "name": "vers:unknown/>=17.0.0|<17.2.1", "product": { "name": "vers:unknown/>=17.0.0|<17.2.1", "product_id": "CSAFPID-5779781" } } ], "category": "product_name", "name": "Umbraco-CMS" }, { "branches": [ { "category": "product_version_range", "name": "vers:unknown/>=15.3.1|<16.5.1", "product": { "name": "vers:unknown/>=15.3.1|<16.5.1", "product_id": "CSAFPID-5845057", "product_identification_helper": { "cpe": "cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*" } } }, { "category": "product_version_range", "name": "vers:unknown/>=17.0.0|<17.2.2", "product": { "name": "vers:unknown/>=17.0.0|<17.2.2", "product_id": "CSAFPID-5845055", "product_identification_helper": { "cpe": "cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*" } } } ], "category": "product_name", "name": "umbraco_cms" } ], "category": "vendor", "name": "Umbraco" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-31834", "cwe": { "id": "CWE-862", "name": "Missing Authorization" }, "notes": [ { "category": "description", "text": "Umbraco is an ASP.NET CMS. From 15.3.1 to before 16.5.1 and 17.2.2, A privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships. The affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles. This vulnerability is fixed in 16.5.1 and 17.2.2.", "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-31834" }, { "category": "description", "text": "Umbraco is an ASP.NET CMS. From 15.3.1 to before 16.5.1 and 17.2.2, A privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships. The affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles. This vulnerability is fixed in 16.5.1 and 17.2.2.", "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-31834" }, { "category": "description", "text": "### Description\nA privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships.\n\nThe affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles.\n\n### Impact\nAn authenticated backoffice user may be able to escalate their privileges to Administrator level.\n\nSuccessful exploitation results in full administrative control of the affected Umbraco CMS instance, including unrestricted access to content, user management, and configuration settings.\n\nThe impact is significantly mitigated by the fact that this can only be exploited by a user that has already been given access to the \"Users\" section in the CMS. For most Umbraco setups, such users are already also \"Administrators\".\n\n### Patches\nThe issue is patched in 16.5.1 and 17.2.2.\n\n### Workarounds\nThere is no workaround other than upgrading for setups where they want to have users with permission for the \"Users\" section without also being content with those users also being part of the \"Administrators\" user group.", "title": "github - https://github.com/advisories/GHSA-rhcg-3h8r-v6vp" }, { "category": "description", "text": "### Description\nA privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships.\n\nThe affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles.\n\n### Impact\nAn authenticated backoffice user may be able to escalate their privileges to Administrator level.\n\nSuccessful exploitation results in full administrative control of the affected Umbraco CMS instance, including unrestricted access to content, user management, and configuration settings.\n\nThe impact is significantly mitigated by the fact that this can only be exploited by a user that has already been given access to the \"Users\" section in the CMS. For most Umbraco setups, such users are already also \"Administrators\".\n\n### Patches\nThe issue is patched in 16.5.1 and 17.2.2.\n\n### Workarounds\nThere is no workaround other than upgrading for setups where they want to have users with permission for the \"Users\" section without also being content with those users also being part of the \"Administrators\" user group.", "title": "github - https://api.github.com/advisories/GHSA-rhcg-3h8r-v6vp" }, { "category": "other", "text": "0.0005", "title": "EPSS" }, { "category": "other", "text": "4.5", "title": "NCSC Score" }, { "category": "other", "text": "Is related to CWE-269 (Improper Privilege Management)", "title": "NCSC Score top increasing factors" }, { "category": "other", "text": "Is related to (a version of) an uncommon product", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-5779780", "CSAFPID-5779781", "CSAFPID-5845055", "CSAFPID-5845057" ] }, "references": [ { "category": "external", "summary": "Source - nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31834" }, { "category": "external", "summary": "Source raw - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-31834" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://www.cve.org/CVERecord?id=CVE-2026-31834" }, { "category": "external", "summary": "Source raw - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/31xxx/CVE-2026-31834.json" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-31834" }, { "category": "external", "summary": "Source raw - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - github", "url": "https://github.com/advisories/GHSA-rhcg-3h8r-v6vp" }, { "category": "external", "summary": "Source raw - github", "url": "https://api.github.com/advisories/GHSA-rhcg-3h8r-v6vp" }, { "category": "external", "summary": "Source - github", "url": "https://api.github.com/advisories/GHSA-rhcg-3h8r-v6vp" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd", "url": "https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-rhcg-3h8r-v6vp" }, { "category": "external", "summary": "Reference - github", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31834" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/advisories/GHSA-rhcg-3h8r-v6vp" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.2, "baseSeverity": "HIGH" }, "products": [ "CSAFPID-5779780", "CSAFPID-5779781", "CSAFPID-5845055", "CSAFPID-5845057" ] } ], "title": "CVE-2026-31834" } ] }