CVE-2025-35939
Published: June 2, 2025
Official Description
Craft CMS contains an external control of assumed-immutable web parameter vulnerability. This vulnerability could allow an unauthenticated client to introduce arbitrary values, such as PHP code, to a known local file location on the server. This vulnerability could be chained with CVE-2024-58136 as represented by CVE-2025-32432.
CISA KEV Advisory
Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
Craft CMS contains an external control of assumed-immutable web parameter vulnerability. This vulnerability could allow an unauthenticated client to introduce arbitrary values, such as PHP code, to a known local file location on the server. This vulnerability could be chained with CVE-2024-58136 as represented by CVE-2025-32432.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Risk Analysis
Craft CMS contains a vulnerability where an unauthenticated client can introduce arbitrary values, such as PHP code, to a known local file location on the server. The high EPSS score of 0.20814 indicates a significant likelihood of exploitation, making this a critical concern. Its inclusion in CISA's KEV further confirms active exploitation.
This vulnerability has been actively exploited in the wild, and its presence in CISA's KEV confirms its use by threat actors. The ability for an unauthenticated client to introduce arbitrary values suggests it is remotely exploitable.
Craft CMS users should apply all available security updates to address the external control of assumed-immutable web parameter vulnerability. Implement strong input validation and restrict file upload capabilities to trusted users and file types.
Technical Analysis
CVE-2025-35939 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2025-35939 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (2)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2025-35939 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1