CVE-2026-25133

A stored cross-site scripting (XSS) vulnerability was identified in the SVG sanitization logic. The regex pattern used to strip on* event handler attributes could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries.

Workarounds

If upgrading immediately is not possible:

• Disable SVG uploads by adding svg to the blocked extensions in media configuration
• Set media.clean_vectors to true in configuration (enabled by default)

References

• Reported by Pentest-Tools.com

• Stored XSS via malicious SVG files uploaded through the Media Manager
• Could allow privilege escalation if a superuser views or embeds the malicious SVG
• Requires authenticated backend access with media upload permissions (media.library.create)
• SVG must be viewed or embedded in a page to trigger

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2026-25133 has a CVSS score of 4.8 (Medium). The vector is network-reachable, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.1.10, 3.7.14); upgrading removes the vulnerable code path.

Kodem intelligence

The vulnerability has been patched in v3.7.14 and v4.1.10. All users are encouraged to upgrade to the latest patched version.

1. What is CVE-2026-25133? CVE-2026-25133 is a medium-severity cross-site scripting (XSS) vulnerability in october/rain (composer), affecting versions >= 4.0.0, <= 4.1.9. It is fixed in 4.1.10, 3.7.14. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2026-25133? CVE-2026-25133 has a CVSS score of 4.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of october/rain are affected by CVE-2026-25133? october/rain (composer) versions >= 4.0.0, <= 4.1.9 is affected.
4. Is there a fix for CVE-2026-25133? Yes. CVE-2026-25133 is fixed in 4.1.10, 3.7.14. Upgrade to this version or later.
5. Is CVE-2026-25133 exploitable, and should I be worried? Whether CVE-2026-25133 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-25133 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-25133?
   • Upgrade october/rain to 4.1.10 or later
   • Upgrade october/rain to 3.7.14 or later