What’s Vulnerable › Vulnerabilities

CVE-2026-112951: ApostropheCMS: Color field validation bypass allows stored XSS via HTML appended after rgb()/hsl() prefix

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-20 · updated 2026-10-20
• Weakness: CWE-79

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.

Affected products

• apostrophecms apostrophe: before 4.34.0

References

• https://github.com/apostrophecms/apostrophe/commit/06e4b377f3c360f9e89c32dccd7e505ad5ddf498
• https://github.com/apostrophecms/apostrophe/commit/40b989b1a9dd23d30029b8ce7668634265cfe5ea
• https://github.com/apostrophecms/apostrophe/releases/tag/apostrophe@4.34.0
• https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-vmgj-9cwm-cf3h
• https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-vmgj-9cwm-cf3h

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