CVE-2025-35939: Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 2 Jun 2025, 26 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 1.3%
EPSS score, percentile 71.4 of all scored records
- How severe?
- 6.9 Medium
CVSS v4.0 base score, given by the CNA
- What should I do?
Required action (CISA), due 23 Jun 2025: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected: before 5.7.5; before 4.15.3
Unaffected: 5.7.5; 4.15.3
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: 23 June 2025.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 5.7.5 |
| Unaffected | 5.7.5 |
| Affected | before 4.15.3 |
| Unaffected | 4.15.3 |
Versions not listed are: unknown.
Versions the record lists as unaffected: 5.7.5, 4.15.3.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this 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.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2025-35939 to its Known Exploited Vulnerabilities (KEV) catalog on 2 Jun 2025.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 23 Jun 2025.
- The CVE record was published on 7 May 2025, 26 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 6.9 (Medium), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 1.3% (percentile 71.4), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Craft CMS stores user-provided content in session files
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-472: External Control of Assumed-Immutable Web Parameter
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 7 May 2025 | CVE record published |
| 2 Jun 2025 | Added to CISA KEV |
| 23 Jun 2025 | CISA due date for the required action |
| 26 Feb 2026 | CVE record last updated |
References
More exploited Craft CMS vulnerabilities
- CVE-2025-32432: Craft CMS Code Injection Vulnerability
- CVE-2024-56145: Craft CMS Code Injection Vulnerability
- CVE-2025-23209: Craft CMS Code Injection Vulnerability