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Fencer Vulns
medium 5.3

CVE-2025-35939 kev in the critical feed json

Craft CMS stores user-provided content in session files

published 2025-05-07 18 mo ago modified 2026-06-17 4 mo ago also GHSA-7vrx-9684-xrf2 , EUVD-2025-13951

cvss
5.3
version 3.1, CNA
cisa kev
Exploited
added 2025-06-02
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

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.

Patch / fix

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

  • packagist craftcms/cms 4.15.3, 5.7.5
  • Craft CMS 4.15.3, 5.7.5

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa vex VA-25-147-01 updated cvss 5.3

Craft CMS stores user-provided content session files

  • Craft CMS <5.7.5, <4.15.3
    affected: vendor fix github.com
  • Craft CMS 5.7.5, 4.15.3
    fixed: vendor fix github.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Timeline

  1. Published
  2. Added to CISA KEV
  3. CISA SSVC: exploitation active
  4. CISA patch deadline

Known exploited

Added
17 mo ago
Patch by
2025-06-23 (16 mo ago)
Ransomware
Not known
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vendor, product
Craft CMS, Craft CMS
CISA name
Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability

ATT&CK techniques

How it is exploited and what it leads to, in MITRE ATT&CK terms.

  • T1190 Exploit Public-Facing Application exploitation
  • T1505.003 Web Shell primary impact
  • T1059 Command and Scripting Interpreter secondary impact

kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

1.37% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 6.9 CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:H

Affected packages

ecosystem package affected fixed in
packagist craftcms/cms
>=5.0.0-alpha.1, <5.7.5
<4.15.3
5.7.5
4.15.3

Affected products

  • Craft CMS

Classification

Weakness
  • CWE-472 External Control of Assumed-Immutable Web Parameter

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.