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.
History

Wed, 11 Mar 2026 18:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Craft has Reflective XSS via incomplete return URL sanitization
Weaknesses CWE-116
CWE-79
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-11T17:37:19.065Z

Reserved: 2026-03-09T19:02:25.012Z

Link: CVE-2026-31859

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-11T18:16:24.710

Modified: 2026-03-11T18:16:24.710

Link: CVE-2026-31859

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.