CVE-2026-31859

MEDIUM

6.1

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.

CVE Details

CVSS v3.1 Score6.1

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionREQUIRED

Published3/11/2026

Last Modified3/17/2026

Sourcenvd

Honeypot Sightings0

Affected Products

craftcms:craft_cms

Weaknesses (CWE)

CWE-79CWE-116

References

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

IOC Correlations

No correlations recorded

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