GHSA-52CW-PVQ9-9M5V

Silverstripe uses TinyMCE which allows svg files linked in object tags

References:

• https://www.silverstripe.org/download/security-releases/ss-2024-001
• https://github.com/advisories/GHSA-5359-pvf2-pw78

TinyMCE v6 has a configuration value convert_unsafe_embeds set to false which allows svg files containing javascript to be used in <object> or <embed> tags, which can be used as a vector for XSS attacks.

Note that <embed> tags are not allowed by default.

After patching the default value of convert_unsafe_embeds will be set to true. This means that <object> tags will be converted to iframes instead the next time the page is saved, which may break any pages that rely upon previously saved <object> tags. Developers can override this configuration if desired to revert to the original behaviour.

We reviewed the potential impact of this vulnerability within the context of Silverstripe CMS. We concluded this is a medium impact vulnerability given how TinyMCE is used by Silverstripe CMS.

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-52CW-PVQ9-9M5V has a CVSS score of 5.4 (Medium). The vector is network-reachable, low 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 (5.2.16); upgrading removes the vulnerable code path.

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1. What is GHSA-52CW-PVQ9-9M5V? GHSA-52CW-PVQ9-9M5V is a medium-severity cross-site scripting (XSS) vulnerability in silverstripe/framework (composer), affecting versions < 5.2.16. It is fixed in 5.2.16. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is GHSA-52CW-PVQ9-9M5V? GHSA-52CW-PVQ9-9M5V has a CVSS score of 5.4 (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-52CW-PVQ9-9M5V? silverstripe/framework (composer) versions < 5.2.16 is affected.
4. Is there a fix for GHSA-52CW-PVQ9-9M5V? Yes. GHSA-52CW-PVQ9-9M5V is fixed in 5.2.16. Upgrade to this version or later.
5. Is GHSA-52CW-PVQ9-9M5V exploitable, and should I be worried? Whether GHSA-52CW-PVQ9-9M5V 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-52CW-PVQ9-9M5V 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-52CW-PVQ9-9M5V? Upgrade silverstripe/framework to 5.2.16 or later.

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