October CMS has Stored XSS via SVG Filter Bypass
October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the SVG sanitization logic. The regex pattern used to strip event handler attributes (such as onclick or onload) could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries, allowing malicious SVG files to be uploaded through the Media Manager with embedded JavaScript. Exploitation could lead to privilege escalation if a superuser views or embeds the malicious SVG, and requires authenticated backend access with media upload permissions. The SVG must be viewed or embedded in a page for the payload to trigger. This issue has been fixed in versions 3.7.14 and 4.1.10.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-25133
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 17:15 UTC · Revision 1
Source evidence
October CMS has Stored XSS via SVG Filter Bypass
core-osv · Original sourcePublished 14 Apr 2026, 20:47 UTC
October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the SVG sanitization logic. The regex pattern used to strip event handler attributes (such as onclick or onload) could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries, allowing malicious SVG files to be uploaded through the Media Manager with embedded JavaScript. Exploitation could lead to privilege escalation if a superuser views or embeds the malicious SVG, and requires authenticated backend access with media upload permissions. The SVG must be viewed or embedded in a page for the payload to trigger. This issue has been fixed in versions 3.7.14 and 4.1.10.
osv:CVE-2026-25133
Complete source record
{
"id": "718bf9dfb3de537065ebda356371207786dd59a5822bb60be236c3f32b7296c8",
"url": "https://osv.dev/vulnerability/CVE-2026-25133",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "October CMS has Stored XSS via SVG Filter Bypass",
"summary": "October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the SVG sanitization logic. The regex pattern used to strip event handler attributes (such as onclick or onload) could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries, allowing malicious SVG files to be uploaded through the Media Manager with embedded JavaScript. Exploitation could lead to privilege escalation if a superuser views or embeds the malicious SVG, and requires authenticated backend access with media upload permissions. The SVG must be viewed or embedded in a page for the payload to trigger. This issue has been fixed in versions 3.7.14 and 4.1.10.",
"evidence": "osv:CVE-2026-25133",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-25133",
"aliases": [
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"GHSA-gcqv-f29m-67gr"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
}
],
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"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-25133.json"
}
}
],
"modified": "2026-10-28T02:30:38.017222796Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25133.json",
"https://github.com/octobercms/october/security/advisories/GHSA-gcqv-f29m-67gr",
"https://nvd.nist.gov/vuln/detail/CVE-2026-25133"
],
"provider_metadata": {
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],
"cna_assigner": "GitHub_M",
"unresolved_ranges": [
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}
},
"related_cves": [
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"evidence": "/id"
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"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 505221,
"published_at": "2026-04-14T20:47:49.474+00:00"
}