GHSA-M5Q3-MVCR-GC5M

silverstripe/framework BackURL validation bypass with malformed URLs

A carefully constructed malformed URL can be used to circumvent the offsite redirection protection used on BackURL parameters. This could lead to users entering sensitive data in malicious websites instead of the intended one.

Untrusted input controls a URL used for redirection, which can forward users to attacker-controlled sites. Typical impact: phishing and credential harvesting via a trusted domain.

GHSA-M5Q3-MVCR-GC5M has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. 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 (4.0.4, 4.1.1); upgrading removes the vulnerable code path.

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1. What is GHSA-M5Q3-MVCR-GC5M? GHSA-M5Q3-MVCR-GC5M is a high-severity open redirect vulnerability in silverstripe/framework (composer), affecting versions >= 4.0.0-rc1, < 4.0.4. It is fixed in 4.0.4, 4.1.1. Untrusted input controls a URL used for redirection, which can forward users to attacker-controlled sites.
2. How severe is GHSA-M5Q3-MVCR-GC5M? GHSA-M5Q3-MVCR-GC5M has a CVSS score of 7.5 (High). 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-M5Q3-MVCR-GC5M? silverstripe/framework (composer) versions >= 4.0.0-rc1, < 4.0.4 is affected.
4. Is there a fix for GHSA-M5Q3-MVCR-GC5M? Yes. GHSA-M5Q3-MVCR-GC5M is fixed in 4.0.4, 4.1.1. Upgrade to this version or later.
5. Is GHSA-M5Q3-MVCR-GC5M exploitable, and should I be worried? Whether GHSA-M5Q3-MVCR-GC5M 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-M5Q3-MVCR-GC5M 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-M5Q3-MVCR-GC5M?
   • Upgrade silverstripe/framework to 4.0.4 or later
   • Upgrade silverstripe/framework to 4.1.1 or later

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