CVE-2026-31859

EUVD-2026-11261

11.03.2026, 18:16

Craft is a content management system (CMS). The fix for CVE-2025-35939 in craftcms/cms introduced a strip_tags() call in src/web/User.php to sanitize return URLs before they are stored in the session. However, strip_tags() only removes HTML tags (angle brackets) -- it does not inspect or filter URL schemes. Payloads like javascript:alert(document.cookie) contain no HTML tags and pass through strip_tags() completely unmodified, enabling reflected XSS when the return URL is rendered in an href attribute. This vulnerability is fixed in  5.9.7 and 4.17.3.

Cross-site Scripting

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	6.1 MEDIUM	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Affected Products (NVD)

Vendor	Product	Version
craftcms	craft_cms	4.15.3 ≤ 𝑥 < 4.17.3
craftcms	craft_cms	5.7.5 ≤ 𝑥 < 5.9.7

𝑥

= Vulnerable software versions

Common Weakness Enumeration

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

References

https://github.com/craftcms/cms/security/advisories/GHSA-fvwq-45qv-xvhv