ZeroDay Findings
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2025-35939

Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability

Published May 7, 2025 · catalog updated Jun 17, 2026 · Craft CMS

Patch now

CVE-2025-35939 is in the CISA known-exploited catalog, due Jun 23, 2025. Confirm Craft CMS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Medium6.9
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
1.35%
Remediation
Remediation guidance
Affected products
cpe craftcms/craft cms · vendor Craft CMS 0 <4.15.3 · vendor Craft CMS Craft CMS

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe craftcms/craft cmsversion unspecified
  • vendor Craft CMS 0 <4.15.30 <4.15.3
  • vendor Craft CMS Craft CMSversion unspecified

How to fix CVE-2025-35939

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-35939 is in the CISA known-exploited catalog, due Jun 23, 2025. Confirm Craft CMS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with Craft CMS 0 <4.15.3 0 <4.15.3. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-472. EPSS 1.35%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 7, 2025 · Catalog

    Detected

    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]'

  2. Jun 2, 2025 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  3. Jun 23, 2025 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  4. Jun 17, 2026 · Catalog

    Updated

    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]'

Sources

  • CISA KEVConfirmed exploitationCVE-2025-35939

    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.gov
  • CVE.orgVulnerability recordCVE-2025-35939

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-35939

    30-day exploitation probability 1.3%

    first.org
  • EUVDVulnerability recordEUVD-2025-13951

    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

    euvd.enisa.europa.eu
  • NIST NVDVulnerability recordCVE-2025-35939

    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

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2025-35939

    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 wit

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.