CVE-2025-35939: Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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.
Description quoted from the CVE record (assigned by cisa-cg, published 2025-05-07).
Weakness: CWE-472 External Control of Assumed-Immutable Web Parameter
How it can be exploited
Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and no user interaction. Impact: confidentiality none, integrity low, availability none. 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
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: partial.
- On CISA KEV since
- 2025-06-02
- US federal deadline
- 2025-06-23
- Ransomware use
- Not known
Public exploit evidence (Exploit Observer)
Also known as: BDU:2025-08249, CNNVD-202505-1220, EUVD-2025-13951, EUVD-2026-11261, GHSA-7vrx-9684-xrf2, GHSA-fvwq-45qv-xvhv, SNYK-PHP-CRAFTCMSCMS-10184799
VEDAS cluster: VEDAS:CLOVERCHANCE
Exploit Observer has no public exploit code that names this CVE or one of its aliases.
Vulnerability databases and vendor advisories (12)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2025-13951
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2026-11261
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-7vrx-9684-xrf2
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-fvwq-45qv-xvhv
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2025-35939
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/CVE-2025-35939
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/GHSA-7vrx-9684-xrf2
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/GHSA-fvwq-45qv-xvhv
- Vulnerability database or vendor advisory: https://security.snyk.io/vuln/SNYK-PHP-CRAFTCMSCMS-10184799
- Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-35939
- Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202505-1220
- Vulnerability database or vendor advisory: https://www.tenable.com/cve/CVE-2025-35939
7 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.013
some chance of attack soon - VEDAS
- 0.982
strong exploit evidence - On CISA KEV
- Yes, since 2025-06-02
- Detection rule
- None yet
Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Craft CMS | before 5.7.5 before 4.15.3 | 5.7.5 is not affected; 4.15.3 is not affected |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
Exploit Observer also maps it to: craftcms craft_cms, packagist craftcms/cms.
How to fix it
Fixed versions stated in the CVE record: 5.7.5, 4.15.3.
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.
Vendor guidance:
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Government sources
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-35939 (government-resource)
Other references
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.