CVE-2026-112951 ApostropheCMS: Color field validation bypass allows stored XSS via HTML appended after rgb()/hsl() prefix
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-112951?
CVE-2026-112951 is a medium-severity vulnerability in apostrophecms apostrophe, published on 20 Oct 2026.
Official description
ApostropheCMS is an open-source Node.js content management system. Prior to 4.34.0, the color field accepts trailing content after a valid rgb() or hsl() prefix because its TinyColor validation does not require the entire value to match a color. An authenticated user with edit rights can store arbitrary HTML after a valid color prefix. When the stored value is rendered, the payload executes, resulting in stored XSS. This issue is fixed in version 4.34.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-112951?
2 open source packages ship an affected version, including apostrophe.
| Package | Affected | Fixed in |
|---|---|---|
apostrophe npm | All versions | 4.34.0 |
apostrophe npm | All versions | 4.34.0 |
How do I fix CVE-2026-112951?
Upgrade apostrophe to 4.34.0 or later.
Is CVE-2026-112951 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112951 exists.
Sources
Also known as GHSA-vmgj-9cwm-cf3h.