PatchTheCVECVE-2026-33889: ApostropheCMS is an open-source Node.js content management system
CVE-2026-33889 is a medium-severity flaw (CVSS 5.4) affecting apostrophecms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in the @apostrophecms/color-field module, where color values prefixed with -- bypass TinyColor validation intended for CSS custom properties, and the launder.string() call performs only type coercion without stripping HTML metacharacters. These unsanitized values are then concatenated directly into <styl
Why this priority
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.4 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | Required |
| EPSS exploit chance | 0.2% (top 87%) |
| CISA exploited list | No |
| Weakness | CWE-79 |
| Published | 2026-04-15 |
| Last modified | 2026-10-26 |
Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-33889?
apostrophecms: upgrade to 4.29.0. Exact commands for each OS are on this page.
Is CVE-2026-33889 being exploited?
CVE-2026-33889 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-33889 affect?
CVE-2026-33889 affects apostrophecms. Severity is medium (CVSS 5.4). ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in the @apostrophecms/color-field module, where color values prefixed with -- bypass TinyColor
How urgent is CVE-2026-33889?
Priority 27/100. Public exploit reference
Software pages
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