CVE-2026-31951

MediumCVSS 5.7/10Last modified Oct 26, 2026

Description

LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc1 through 0.8.3-rc1, user-created MCP (Model Context Protocol) servers can include arbitrary HTTP headers that undergo credential placeholder substitution. An attacker can create a malicious MCP server with headers containing `{{LIBRECHAT_OPENID_ACCESS_TOKEN}}` (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated. Version 0.8.3-rc2 fixes the issue.

Metrics

CVSS 3.1 5.7/10CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

Weakness enumeration

CWE-200

Affected software

Vendor	Product	Versions
danny-avila	LibreChat	>= v0.8.2-rc1, <= v0.8.3-rc1

References

https://github.com/danny-avila/LibreChat/security/advisories/GHSA-pmw7-gqwj-f954Exploit, Vendor Advisory

Timeline

Published: Mar 27, 2026
Last modified: Oct 26, 2026
NVD status: Analyzed

Related CVEs from 2026

CVE-2026-319528.1Xibo is an open source digital signage platform with a web content management system and Windows display player software. Versions 1.7 throu CVE-2026-319535.4Xibo is an open source digital signage platform with a web content management system and Windows display player software. A stored Cross-Sit CVE-2026-319547.3Emlog is an open source website building system. In 2.6.6 and earlier, the delete_async action (asynchronous delete) lacks a call to LoginAu CVE-2026-319554.9Xibo is an open source digital signage platform with a web content management system and Windows display player software. An authenticated S CVE-2026-319564.3Xibo is an open source digital signage platform with a web content management system and Windows display player software. Prior to version 4 CVE-2026-3195710.0Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From 3.0.0 to before 3.1.0, if Himmelblau is deployed witho CVE-2026-319587.5Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number o CVE-2026-319595.3Quill provides simple mac binary signing and notarization from any platform. Quill before version v0.7.1 contains a Server-Side Request Forg CVE-2026-31965.5An integer overflow vulnerability was found in the virtio-snd device via PCM_INFO requests from the guest. A malicious guest can provide out CVE-2026-319605.3Quill provides simple mac binary signing and notarization from any platform. Quill before version v0.7.1 has unbounded reads of HTTP respons CVE-2026-319615.5Quill provides simple mac binary signing and notarization from any platform. Quill before version v0.7.1 contains an unbounded memory alloca CVE-2026-319628.8HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment dat