CVEs / CVE-2025-35939
CVE-2025-35939: Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
- Known exploited in the CISA KEV catalog since 2 Jun 2025
- medium 5.3 CVSS 3.1 (NVD)
- EPSS 1.34% chance of exploitation in the next 30 days, higher than 71% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
Description
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 and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Craft CMS | before 5.7.5 | 5.7.5 |
| Craft CMS | before 4.15.3 | 4.15.3 |
| Product | Affected | Fixed in |
|---|---|---|
| craftcms/cms (Packagist) | from 5.0.0-alpha.1, before 5.7.5 | 5.7.5 |
| craftcms/cms (Packagist) | before 4.15.3 | 4.15.3 |
Package versions from GHSA-7vrx-9684-xrf2.
Exploitation
| In CISA KEV since | 2 Jun 2025 |
|---|---|
| Due date for US federal agencies | 23 Jun 2025 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NScored by NVD |
|---|---|
| Weakness | CWE-472 |
References
- CVE-2025-35939 on NVD
- CVE-2025-35939 in the CISA KEV catalog
- https://github.com/craftcms/cms/pull/17220 (cited by CISA)
- CVE-2025-35939 on OSV
- https://github.com/craftcms/cms/pull/17220 Patch
- https://github.com/craftcms/cms/releases/tag/4.15.3 Release Notes
- https://github.com/craftcms/cms/releases/tag/5.7.5 Release Notes
- https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-25-147-01.json Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2025-35939 VDB Entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-35939 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.