Auth bypass in Danny-Avila Librechat
CVE-2026-54029
LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.4-rc1, the DELETE /api/messages/:conversationId/:messageId endpoint allows any authenticated user to delete any other user's messages. The validateMessageReq middleware only validates that the conversationId belongs to the requesting user, but the handler calls deleteMessages({ messageId }) using only the messageId as the MongoDB filter — without adding a user constraint. An attacker provides their own valid conversationId (to pass validation) and the victim's messageId (to target deletion), resulting in permanent, irrecoverable message deletion. This vulnerability is fixed in 0.8.4-rc1.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Danny-Avila Librechat — versions < 0.8.4-rc1
- Librechat
Weakness classification (CWE)
References
- github.com/danny-avila/LibreChat/security/advisories/GHSA-8892-xj8q-59xc (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-54029?
- CVE-2026-54029 is a medium-severity vulnerability in Danny-Avila Librechat, classified under Missing Authorization. CVSS score: 5.3/10. Published 2026-06-25.
- How severe is CVE-2026-54029?
- Medium severity. CVSS v3 base score is 5.3 out of 10.