CVE-2025-35939

CVE-2025-35939 is a medium-severity (CVSS 5.3) vulnerability in Craft CMS Craft CMS. CISA added it to the Known Exploited Vulnerabilities catalog on June 2, 2025, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by June 23, 2025. CISA does not currently list it as used in ransomware campaigns. Craft CMS has 4 vulnerabilities in the KEV catalog, 0 of them linked to ransomware.

Craft CMS stores arbitrary content provided by unauthenticated users in session files. This content could be accessed and executed, possibly using an independent vulnerability. Craft CMS redirects requests that require authentication to the login page and generates a session file on the server at '/var/lib/php/sessions'. Such session files are named 'sess_[session_value]', where '[session_value]' is provided to the client in a 'Set-Cookie' response header. Craft CMS stores the return URL requested by the client without sanitizing parameters. Consequently, an unauthenticated client can introduce arbitrary values, such as PHP code, to a known local file location on the server. Craft CMS versions 5.7.5 and 4.15.3 have been released to address this issue.

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

• https://github.com/craftcms/cms/pull/17220
• https://github.com/craftcms/cms/releases/tag/4.15.3
• https://github.com/craftcms/cms/releases/tag/5.7.5
• https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-25-147-01.json
• https://www.cve.org/CVERecord?id=CVE-2025-35939
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-35939