CVE-2025-35939
Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 23 June 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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 4.0
- 6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 1.35% probability · 71th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 2 June 2025 · due 23 June 2025
- Weakness
- CWE-472
- Affected
- craftcms/craft cms
- Source
- 9119a7d8-5eab-497f-8521-727c672e3725
EPSS 1.3% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://github.com/craftcms/cms/pull/17220 ; https://nvd.nist.gov/vuln/detail/CVE-2025-35939
References
- https://github.com/craftcms/cms/pull/17220Patch
- https://github.com/craftcms/cms/releases/tag/4.15.3Release Notes
- https://github.com/craftcms/cms/releases/tag/5.7.5Release Notes
- https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-25-147-01.jsonThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2025-35939VDB Entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-35939US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.