CVE-2026-31859

MEDIUM

Craft CMS - XSS

Title source: llm
STIX 2.1

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.

Scores

CVSS v3 6.1
EPSS 0.0003
EPSS Percentile 10.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-116 CWE-79
Status published
Products (1)
craftcms/craft_cms 4.15.3 - 4.17.3
Published Mar 11, 2026
Tracked Since Mar 12, 2026