GHSA-MPQJ-F4V3-334H

Silverstripe Cross-site scripting vulnerability in VersionedRequestFilter

A cross-site scripting vulnerability in VersionedRequestFilter has been found.

If an incoming user request should not be able to access the requested stage, an error message is created for display on the CMS login page that they are redirected to. In this error message, the URL of the requested page is interpolated into the error message without being escaped; hence, arbitrary HTML can be injected into the CMS login page.

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.

GHSA-MPQJ-F4V3-334H has a CVSS score of 6.1 (Medium). The vector is network-reachable, no 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 (3.3.3, 3.4.1); upgrading removes the vulnerable code path.

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1. What is GHSA-MPQJ-F4V3-334H? GHSA-MPQJ-F4V3-334H is a medium-severity cross-site scripting (XSS) vulnerability in silverstripe/framework (composer), affecting versions >= 3.3.2, < 3.3.3. It is fixed in 3.3.3, 3.4.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is GHSA-MPQJ-F4V3-334H? GHSA-MPQJ-F4V3-334H has a CVSS score of 6.1 (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 silverstripe/framework are affected by GHSA-MPQJ-F4V3-334H? silverstripe/framework (composer) versions >= 3.3.2, < 3.3.3 is affected.
4. Is there a fix for GHSA-MPQJ-F4V3-334H? Yes. GHSA-MPQJ-F4V3-334H is fixed in 3.3.3, 3.4.1. Upgrade to this version or later.
5. Is GHSA-MPQJ-F4V3-334H exploitable, and should I be worried? Whether GHSA-MPQJ-F4V3-334H 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 GHSA-MPQJ-F4V3-334H 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 GHSA-MPQJ-F4V3-334H?
   • Upgrade silverstripe/framework to 3.3.3 or later
   • Upgrade silverstripe/framework to 3.4.1 or later

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