What is CVE-2026-33889?

CVE-2026-33889 is a medium-severity vulnerability in Apostrophecms Apostrophe, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-15.

How severe is CVE-2026-33889?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Apostrophecms Apostrophe

CVE-2026-33889

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…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (11.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

Affected products

Apostrophecms Apostrophe — versions < 4.29.0
Apostrophecms

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33889?: CVE-2026-33889 is a medium-severity vulnerability in Apostrophecms Apostrophe, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-15.
How severe is CVE-2026-33889?: Medium severity. CVSS v3 base score is 5.4 out of 10.