# CVE-2024-36857: Jan - Arbitrary File Read

> Live exploitation tracking for CVE-2024-36857 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2024-36857

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 7.5
- **Public exploit available:** Yes
- **Affected products:** Menloresearch Jan
- **Weaknesses:** CWE-31 (Path Traversal: 'dir\..\..\filename')
- **Tags:** ai_mcp

## Description

Jan v0.4.12 was discovered to contain an arbitrary file read vulnerability via the /v1/app/readFileSync interface.

## CrowdSec analysis

[CVE-2024-36857](https://euvd.enisa.europa.eu/vulnerability/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.
In addition, according to the CrowdSec network, attack volume against CVE-2024-36857 has dipped slightly compared to the previous week. Although still commonly targeted, the decline suggests a cooling-off period. Long-term relevance remains, but attention is waning.

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

## Timeline

- 2024-06-04: CVE Published. CVE-2024-36857 is published to NVD.
- 2025-09-24: Rule Released. CrowdSec releases a rule to detect CVE-2024-36857 exploitation attempts against the CrowdSec Network.
- 2025-09-25: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2024-36857 for the first time.

## References

- https://github.com/HackAllSec/CVEs/tree/main/Jan%20AFR%20vulnerability
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2024/CVE-2024-36857.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2024-36857) follows observed exploitation activity for CVE-2024-36857. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.