CVE-2026-31951: danny-avila LibreChat · Information Exposure
Affects danny-avila LibreChatSource CVE Database V5
Not known to be exploited · CVSS 6.8 Medium · fixed in 0.8.3 : update danny-avila LibreChat when convenient.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.8.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 27 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| danny-avilaLibreChat | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should upgrade LibreChat to version 0.8.3-rc2 or later, where this vulnerability is fixed. Since this is a client-side application vulnerability and not a cloud service, remediation requires applying the official patch by updating the software. Patch status is confirmed fixed in version 0.8.3-rc2.
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.