Jan - Arbitrary File Read (CVE-2024-36857)

CVE-2024-36857 is an arbitrary file read vulnerability in Jan v0.4.12, allowing remote attackers to access sensitive files on the server via the /v1/app/readFileSync interface. This flaw could be exploited to leak confidential information, potentially aiding in further attacks or unauthorized data exposure.

CrowdSec has been tracking this vulnerability and its exploits since 24th of September 2025.

Insights from the CrowdSec network reveal that the attackers trying to exploit CVE-2024-36857 are composed of a fairly even mix of opportunistic and targeted actors. Some attackers employ preliminary reconnaissance, while others use indiscriminate scanning. Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2024-36857 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2024-36857 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.

Attackers exploit the /v1/app/readFileSync endpoint by sending crafted POST requests with path traversal payloads to read arbitrary files from the server filesystem.