Craft CMS up to 4.15.2/5.7.4 Response Header session_value external control of assumed-immutable web parameter

CVSS Meta Temp Score
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CTI Interest Score
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5.2$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in Craft CMS up to 4.15.2/5.7.4. This vulnerability affects unknown code of the component Response Header Handler. Such manipulation of the argument session_value leads to external control of assumed-immutable web parameter. This vulnerability is referenced as CVE-2025-35939. It is possible to launch the attack remotely. Furthermore, an exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Craft CMS up to 4.15.2/5.7.4. It has been rated as problematic. Affected by this issue is an unknown code block of the component Response Header Handler. The manipulation of the argument session_value with an unknown input leads to a external control of assumed-immutable web parameter vulnerability. Using CWE to declare the problem leads to CWE-472. The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields. Impacted is integrity. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2025-35939 since 04/15/2025. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details as well as a exploit are known.

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 253648 (Craft CMS < 4.15.3 / 5.x < 5.7.5 External Control of Assumed-Immutable Web Parameter), which helps to determine the existence of the flaw in a target environment. This issue was added on 06/02/2025 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 06/23/2025:

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

Upgrading to version 4.15.3 or 5.7.5 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (253648) and EUVD (EUVD-2025-13951). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔍
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CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.3
NVD Vector: 🔍

CNA Base Score: 5.3
CNA Vector (cisa-cg): 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: External control of assumed-immutable web parameter
CWE: CWE-472
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Attacked

EPSS Score: 🔍
EPSS Percentile: 🔍

KEV Added: 🔍
KEV Due: 🔍
KEV Remediation: 🔍
KEV Ransomware: 🔍
KEV Notice: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 253648
Nessus Name: Craft CMS < 4.15.3 / 5.x < 5.7.5 External Control of Assumed-Immutable Web Parameter

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: CMS 4.15.3/5.7.5
Patch: github.com

Timelineinfo

04/15/2025 🔍
05/08/2025 +23 days 🔍
05/08/2025 +0 days 🔍
08/23/2025 +107 days 🔍

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2025-35939 (🔍)
GCVE (CVE): GCVE-0-2025-35939
GCVE (VulDB): GCVE-100-307970
EUVD: 🔍
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 05/08/2025 08:00
Updated: 08/23/2025 15:12
Changes: 05/08/2025 08:00 (79), 05/14/2025 14:41 (1), 05/29/2025 07:18 (1), 06/02/2025 23:22 (13), 06/04/2025 07:17 (9), 08/23/2025 15:12 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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