What is CVE-2026-40186?

CVE-2026-40186 is a medium-severity vulnerability in Apostrophecms Apostrophe, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-15.

How severe is CVE-2026-40186?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Apostrophecms Apostrophe

CVE-2026-40186

ApostropheCMS is an open-source Node.js content management system. A regression introduced in commit 49d0bb7, included in versions 2.17.1 of the ApostropheCMS-maintained sanitize-html package bypasses allowedTags enforcement for text insid…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.000 (3.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Apostrophecms Apostrophe — versions >= 4.28.0, < 4.29.0
Apostrophecms Sanitize-html — versions >= 2.17.1, < 2.17.2

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-9mrh-v2v3-xpfm (x_refsource_CONFIRM)
https://github.com/apostrophecms/apostrophe/commit/7ca2d16237c72718ef7e5c7ae0458e6027ac4f64 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-40186?: CVE-2026-40186 is a medium-severity vulnerability in Apostrophecms Apostrophe, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-15.
How severe is CVE-2026-40186?: Medium severity. CVSS v3 base score is 6.1 out of 10.