Auth bypass in Danny-Avila Librechat
CVE-2026-31944
LibreChat is a ChatGPT clone with additional features. From 0.8.2 to 0.8.2-rc3, The MCP (Model Context Protocol) OAuth callback endpoint accepts the redirect from the identity provider and stores OAuth tokens for the user who initiated the flow, without verifying that the browser hitting the redirect URL is logged in or that the logged-in user matches the initiator. An attacker can send the authorization URL to a victim; when the victim completes the flow, the victim’s OAuth tokens are stored on the attacker’s LibreChat account, enabling account takeover of the victim’s MCP-linked services (e.g. Atlassian, Outlook). This vulnerability is fixed in 0.8.3-rc1.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (19.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000
Affected products
- Danny-Avila Librechat — versions >= v0.8.2, <= 0.8.2-rc3
- Librechat — versions 0.8.2
Weakness classification (CWE)
References
- github.com/danny-avila/LibreChat/security/advisories/GHSA-vf7j-7mrx-hp7g (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-31944?
- CVE-2026-31944 is a high-severity vulnerability in Danny-Avila Librechat, classified under Missing Authentication for Critical Function. CVSS score: 7.6/10. Published 2026-03-13.
- How severe is CVE-2026-31944?
- High severity. CVSS v3 base score is 7.6 out of 10.