Background exploitation KEV catalog No authentication
CVE-2025-35939

Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability

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…

CheckOps priority index
4.6/10 Patch within 7 days
Severity6.9
Probability0.1
Exploitation3/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 1.3% higher than 71.5% of CVEs
CVSS 4.0 6.9 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/
Exploited for 519 days 02 Jun 2025
CISA due date 23 Jun 2025 for US federal agencies

Exploitation probability EPSS · FIRST

05010025 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 3 / 5

  • KEV catalog (CISA)02 Jun 2025
  • Exploited in EUVD (ENISA)02 Jun 2025
  • Used by ransomwareno
  • EPSS above 10 %1.3%
  • No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

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

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

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.

Affected products

CMSCraft CMS
Affected versions
  • 0 <4.15.3
  • 0 <5.7.5
Weaknesses (CWE)

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

References

Other exploited vulnerabilities from the same vendor

  • CVE-2025-32432Craft CMS Code Injection Vulnerability
    9.4 · Background exploitation
  • CVE-2024-56145Craft CMS Code Injection Vulnerability
    9.0 · Background exploitation
  • CVE-2025-23209Craft CMS Code Injection Vulnerability
    5.7 · Background exploitation

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities