CVE-2026-31951
- Source
- https://cve.org/CVERecord?id=CVE-2026-31951
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31951.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-31951
- Aliases
-
- GHSA-pmw7-gqwj-f954
- Published
- 2026-03-27T19:29:25.892Z
- Modified
- 2026-07-15T02:18:57.344787165Z
- Severity
-
- 6.8 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N CVSS Calculator
- Summary
- LibreChat's MCP Server Header Injection Enables OAuth Token Theft
- Details
-
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. - Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-200" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31951.json" }- References
Affected packages
Git / github.com/danny-avila/librechat
Affected ranges
- Type
- GIT
- Repo
- https://github.com/danny-avila/librechat
- Events
-
IntroducedFixedIntroducedLast affected
- Database specific
{ "source": [ "CPE_RANGE", "CPE_STRING" ], "cpe": [ "cpe:2.3:a:librechat:librechat:*:*:*:*:*:*:*:*", "cpe:2.3:a:librechat:librechat:0.8.3:rc1:*:*:*:*:*:*" ], "extracted_events": [ { "introduced": "0.8.2" }, { "fixed": "0.8.3" }, { "introduced": "0.8.3-rc1" }, { "last_affected": "0.8.3-rc1" } ] }