{ "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-2026-30913", "tracking": { "current_release_date": "2026-03-23T04:07:40.493325Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-30913", "initial_release_date": "2026-03-09T23:38:52.564526Z", "revision_history": [ { "date": "2026-03-09T23:38:52.564526Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (3).| CWES updated (1)." }, { "date": "2026-03-09T23:38:54.019285Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-03-10T01:39:53.400522Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (4).| CWES updated (1)." }, { "date": "2026-03-10T01:39:57.509216Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-03-10T06:31:01.573565Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (17).| Product Identifiers created (16).| References created (3).| CWES updated (1)." }, { "date": "2026-03-10T07:34:46.275061Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-03-10T14:21:01.120811Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-10T14:21:03.682643Z", "number": "8", "summary": "NCSC Score updated." }, { "date": "2026-03-10T14:38:46.161281Z", "number": "9", "summary": "Unknown change." }, { "date": "2026-03-10T18:30:28.141733Z", "number": "10", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)." }, { "date": "2026-03-10T18:30:39.013496Z", "number": "11", "summary": "NCSC Score updated." }, { "date": "2026-03-10T19:58:26.805121Z", "number": "12", "summary": "References created (2)." }, { "date": "2026-03-11T00:33:07.799500Z", "number": "13", "summary": "References created (2)." }, { "date": "2026-03-19T15:28:52.425026Z", "number": "14", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (6).| CWES updated (1)." }, { "date": "2026-03-20T09:33:40.243132Z", "number": "15", "summary": "Source connected.| CVE status created. (valid)| EPSS created." } ], "status": "interim", "version": "15" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/0.1.0-beta.16.1", "product": { "name": "vers:unknown/0.1.0-beta.16.1", "product_id": "CSAFPID-5773639", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@0.1.0-beta.16.1" } } }, { "category": "product_version_range", "name": "vers:unknown/<1.8.3", "product": { "name": "vers:unknown/<1.8.3", "product_id": "CSAFPID-5772723" } }, { "category": "product_version_range", "name": "vers:unknown/>=0|<1.8.3", "product": { "name": "vers:unknown/>=0|<1.8.3", "product_id": "CSAFPID-5773655" } }, { "category": "product_version_range", "name": "vers:unknown/v0.1.0-beta.15", "product": { "name": "vers:unknown/v0.1.0-beta.15", "product_id": "CSAFPID-5773640", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v0.1.0-beta.15" } } }, { "category": "product_version_range", "name": "vers:unknown/v0.1.0-beta.16", "product": { "name": "vers:unknown/v0.1.0-beta.16", "product_id": "CSAFPID-5773641", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v0.1.0-beta.16" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.0.0", "product": { "name": "vers:unknown/v1.0.0", "product_id": "CSAFPID-5773642", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.0.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.1.0", "product": { "name": "vers:unknown/v1.1.0", "product_id": "CSAFPID-5773643", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.1.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.2.0", "product": { "name": "vers:unknown/v1.2.0", "product_id": "CSAFPID-5773644", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.2.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.3.0", "product": { "name": "vers:unknown/v1.3.0", "product_id": "CSAFPID-5773645", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.3.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.3.1", "product": { "name": "vers:unknown/v1.3.1", "product_id": "CSAFPID-5773646", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.3.1" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.4.0", "product": { "name": "vers:unknown/v1.4.0", "product_id": "CSAFPID-5773647", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.4.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.5.0", "product": { "name": "vers:unknown/v1.5.0", "product_id": "CSAFPID-5773648", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.5.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.6.0", "product": { "name": "vers:unknown/v1.6.0", "product_id": "CSAFPID-5773649", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.6.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.6.1", "product": { "name": "vers:unknown/v1.6.1", "product_id": "CSAFPID-5773650", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.6.1" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.7.0", "product": { "name": "vers:unknown/v1.7.0", "product_id": "CSAFPID-5773651", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.7.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.8.0", "product": { "name": "vers:unknown/v1.8.0", "product_id": "CSAFPID-5773652", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.8.0" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.8.1", "product": { "name": "vers:unknown/v1.8.1", "product_id": "CSAFPID-5773653", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.8.1" } } }, { "category": "product_version_range", "name": "vers:unknown/v1.8.2", "product": { "name": "vers:unknown/v1.8.2", "product_id": "CSAFPID-5773654", "product_identification_helper": { "purl": "pkg:composer/flarum/nicknames@v1.8.2" } } } ], "category": "product_name", "name": "nicknames" } ], "category": "vendor", "name": "flarum" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-30913", "cwe": { "id": "CWE-79", "name": "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')" }, "notes": [ { "category": "description", "text": "Flarum is open-source forum software. When the flarum/nicknames extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname is inserted verbatim into plain-text notification emails, and recipients may be misled into visiting attacker-controlled domains.", "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-30913" }, { "category": "description", "text": "## Summary\n\nWhen the `flarum/nicknames` extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname is inserted verbatim into plain-text notification emails, and recipients may be misled into visiting attacker-controlled domains.\n\n## Affected package\n\n- **`flarum/nicknames`** — permissive display name driver that allows special characters; affected since initial release on the `1.x` branch\n\nAny third-party display name driver that permits special characters would be equally affected.\n\n## Variants\n\n1. **Domain autolink** — a nickname such as `nasty.com` is automatically converted to a clickable hyperlink by virtually all email clients (Gmail, Outlook, Apple Mail, Thunderbird).\n2. **Markdown link syntax** — a nickname such as `[CLICK](https://evil.com)` is rendered as a clickable hyperlink by email clients that auto-render markdown in plain-text emails (e.g. Apple Mail, Thunderbird).\n\n## Steps to reproduce\n\n**Variant 1 (autolink — affects all email clients)**\n1. Enable `flarum/nicknames`, set nickname to `nasty.com`\n2. Trigger a notification email to another user (e.g. follow them, mention them)\n3. The nickname appears as a clickable link in the received email\n\n**Variant 2 (markdown — affects markdown-rendering email clients)**\n1. Enable `flarum/nicknames`, set nickname to `[CLICK](https://evil.com)`\n2. Trigger a notification email to another user\n3. In a markdown-rendering email client (e.g. Apple Mail), the nickname appears as a clickable link\n\n## Impact\n\nPhishing / social engineering: victims may be misled into visiting attacker-controlled URLs via links appearing to originate from a trusted platform notification email. Variant 1 is exploitable against virtually all email clients without any special conditions.\n\n- CVSS v3.1: `AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N` — **4.6 Medium**\n\n## Root cause\n\nThe default username-based display name driver constrains values to `[a-zA-Z0-9_-]+`, making it immune. `flarum/nicknames` introduced permissive validation (min/max length and an optional admin-configured regex) that allows arbitrary characters including those meaningful in URL and markdown contexts. This has been the case since the first commit of the extension.\n\n## Proposed fix\n\n- Add validation in `flarum/nicknames` to reject or sanitize nicknames containing characters that email clients may interpret as URLs or markdown links\n- Alternatively, sanitize the display name before insertion into notification email bodies so that legitimate nicknames like `Jane.Smith` are preserved but rendered safely\n\n## References\n\n- Bug bounty submission: SBB-L4ZVAFH8 (Intigriti)", "title": "github - https://github.com/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "description", "text": "## Summary\n\nWhen the `flarum/nicknames` extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname is inserted verbatim into plain-text notification emails, and recipients may be misled into visiting attacker-controlled domains.\n\n## Affected package\n\n- **`flarum/nicknames`** — permissive display name driver that allows special characters; affected since initial release on the `1.x` branch\n\nAny third-party display name driver that permits special characters would be equally affected.\n\n## Variants\n\n1. **Domain autolink** — a nickname such as `nasty.com` is automatically converted to a clickable hyperlink by virtually all email clients (Gmail, Outlook, Apple Mail, Thunderbird).\n2. **Markdown link syntax** — a nickname such as `[CLICK](https://evil.com)` is rendered as a clickable hyperlink by email clients that auto-render markdown in plain-text emails (e.g. Apple Mail, Thunderbird).\n\n## Steps to reproduce\n\n**Variant 1 (autolink — affects all email clients)**\n1. Enable `flarum/nicknames`, set nickname to `nasty.com`\n2. Trigger a notification email to another user (e.g. follow them, mention them)\n3. The nickname appears as a clickable link in the received email\n\n**Variant 2 (markdown — affects markdown-rendering email clients)**\n1. Enable `flarum/nicknames`, set nickname to `[CLICK](https://evil.com)`\n2. Trigger a notification email to another user\n3. In a markdown-rendering email client (e.g. Apple Mail), the nickname appears as a clickable link\n\n## Impact\n\nPhishing / social engineering: victims may be misled into visiting attacker-controlled URLs via links appearing to originate from a trusted platform notification email. Variant 1 is exploitable against virtually all email clients without any special conditions.\n\n- CVSS v3.1: `AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N` — **4.6 Medium**\n\n## Root cause\n\nThe default username-based display name driver constrains values to `[a-zA-Z0-9_-]+`, making it immune. `flarum/nicknames` introduced permissive validation (min/max length and an optional admin-configured regex) that allows arbitrary characters including those meaningful in URL and markdown contexts. This has been the case since the first commit of the extension.\n\n## Proposed fix\n\n- Add validation in `flarum/nicknames` to reject or sanitize nicknames containing characters that email clients may interpret as URLs or markdown links\n- Alternatively, sanitize the display name before insertion into notification email bodies so that legitimate nicknames like `Jane.Smith` are preserved but rendered safely\n\n## References\n\n- Bug bounty submission: SBB-L4ZVAFH8 (Intigriti)", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Packagist%2FGHSA-3c4m-j3g4-hh25.json?alt=media" }, { "category": "description", "text": "Flarum is open-source forum software. When the flarum/nicknames extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname is inserted verbatim into plain-text notification emails, and recipients may be misled into visiting attacker-controlled domains.", "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-30913" }, { "category": "description", "text": "## Summary\n\nWhen the `flarum/nicknames` extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname is inserted verbatim into plain-text notification emails, and recipients may be misled into visiting attacker-controlled domains.\n\n## Affected package\n\n- **`flarum/nicknames`** — permissive display name driver that allows special characters; affected since initial release on the `1.x` branch\n\nAny third-party display name driver that permits special characters would be equally affected.\n\n## Variants\n\n1. **Domain autolink** — a nickname such as `nasty.com` is automatically converted to a clickable hyperlink by virtually all email clients (Gmail, Outlook, Apple Mail, Thunderbird).\n2. **Markdown link syntax** — a nickname such as `[CLICK](https://evil.com)` is rendered as a clickable hyperlink by email clients that auto-render markdown in plain-text emails (e.g. Apple Mail, Thunderbird).\n\n## Steps to reproduce\n\n**Variant 1 (autolink — affects all email clients)**\n1. Enable `flarum/nicknames`, set nickname to `nasty.com`\n2. Trigger a notification email to another user (e.g. follow them, mention them)\n3. The nickname appears as a clickable link in the received email\n\n**Variant 2 (markdown — affects markdown-rendering email clients)**\n1. Enable `flarum/nicknames`, set nickname to `[CLICK](https://evil.com)`\n2. Trigger a notification email to another user\n3. In a markdown-rendering email client (e.g. Apple Mail), the nickname appears as a clickable link\n\n## Impact\n\nPhishing / social engineering: victims may be misled into visiting attacker-controlled URLs via links appearing to originate from a trusted platform notification email. Variant 1 is exploitable against virtually all email clients without any special conditions.\n\n- CVSS v3.1: `AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N` — **4.6 Medium**\n\n## Root cause\n\nThe default username-based display name driver constrains values to `[a-zA-Z0-9_-]+`, making it immune. `flarum/nicknames` introduced permissive validation (min/max length and an optional admin-configured regex) that allows arbitrary characters including those meaningful in URL and markdown contexts. This has been the case since the first commit of the extension.\n\n## Proposed fix\n\n- Add validation in `flarum/nicknames` to reject or sanitize nicknames containing characters that email clients may interpret as URLs or markdown links\n- Alternatively, sanitize the display name before insertion into notification email bodies so that legitimate nicknames like `Jane.Smith` are preserved but rendered safely\n\n## References\n\n- Bug bounty submission: SBB-L4ZVAFH8 (Intigriti)", "title": "github - https://api.github.com/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "other", "text": "0.00029", "title": "EPSS" }, { "category": "other", "text": "3.8", "title": "NCSC Score" }, { "category": "other", "text": "The value of the most recent EPSS score, Is related to CWE-79 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')), There is cwe data available from source Nvd", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-5772723", "CSAFPID-5773639", "CSAFPID-5773640", "CSAFPID-5773641", "CSAFPID-5773642", "CSAFPID-5773643", "CSAFPID-5773644", "CSAFPID-5773645", "CSAFPID-5773646", "CSAFPID-5773647", "CSAFPID-5773648", "CSAFPID-5773649", "CSAFPID-5773650", "CSAFPID-5773651", "CSAFPID-5773652", "CSAFPID-5773653", "CSAFPID-5773654", "CSAFPID-5773655" ] }, "references": [ { "category": "external", "summary": "Source - cveprojectv5", "url": "https://www.cve.org/CVERecord?id=CVE-2026-30913" }, { "category": "external", "summary": "Source raw - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/30xxx/CVE-2026-30913.json" }, { "category": "external", "summary": "Source - github", "url": "https://github.com/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "external", "summary": "Source raw - github", "url": "https://api.github.com/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Packagist%2FGHSA-3c4m-j3g4-hh25.json?alt=media" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-30913" }, { "category": "external", "summary": "Source raw - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30913" }, { "category": "external", "summary": "Source raw - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-30913" }, { "category": "external", "summary": "Source - github", "url": "https://api.github.com/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; osv", "url": "https://github.com/flarum/framework/security/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; osv", "url": "https://github.com/flarum/nicknames/commit/4dde99729abdce8f6e2a7437c86e38735fdcca28" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; osv", "url": "https://github.com/flarum/nicknames/releases/tag/v1.8." }, { "category": "external", "summary": "Reference - github; osv", "url": "https://github.com/flarum/nicknames/releases/tag/v1.8.3" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/advisories/GHSA-3c4m-j3g4-hh25" }, { "category": "external", "summary": "Reference - github; osv", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30913" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N", "baseScore": 4.6, "baseSeverity": "MEDIUM" }, "products": [ "CSAFPID-5772723", "CSAFPID-5773639", "CSAFPID-5773640", "CSAFPID-5773641", "CSAFPID-5773642", "CSAFPID-5773643", "CSAFPID-5773644", "CSAFPID-5773645", "CSAFPID-5773646", "CSAFPID-5773647", "CSAFPID-5773648", "CSAFPID-5773649", "CSAFPID-5773650", "CSAFPID-5773651", "CSAFPID-5773652", "CSAFPID-5773653", "CSAFPID-5773654", "CSAFPID-5773655" ] } ], "title": "CVE-2026-30913" } ] }