CVE-2025-35939

Known Exploited
Craft CMS stores user-provided content in session files

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.

Category

6.9
CVSS
Severity: Medium
CVSS 4.0 •
CVSS 3.1 •
EPSS 0.13%
KEV Since 
Third-Party Advisory githubusercontent.com
Affected: Craft CMS
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2025-35939?
CVE-2025-35939 has been scored as a medium severity vulnerability.
How to fix CVE-2025-35939?
To fix CVE-2025-35939, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-35939 being actively exploited in the wild?
It is confirmed that CVE-2025-35939 is actively exploited. Be extra cautious if you are using vulnerable components. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-35939?
CVE-2025-35939 affects Craft CMS.
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