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Vulnerabilities

Vulnerability · CVE-2026-31951

LibreChat is a ChatGPT clone with additional features.

Published Mar 27, 2026 · catalog updated Jun 17, 2026 · LibreChat is a ChatGPT

Check if you run it

No confirmed exploitation is on record for CVE-2026-31951. EPSS is 0.35%. Act only if a listed version of LibreChat is a ChatGPT is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (LibreChat is a ChatGPT).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Advisory link
Affected products
cpe librechat/librechat

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 (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated. Version 0.8.3-rc2 fixes the issue.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe librechat/librechat0.8.3

How to fix CVE-2026-31951

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-31951. EPSS is 0.35%. Act only if a listed version of LibreChat is a ChatGPT is installed.

Which versions are affected?

Compare what you have installed with 0.8.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-200: Exposure of Sensitive Information. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 27, 2026 · NIST NVD

    Detected

    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 (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated.

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated.

Sources

  • CVE.orgVulnerability recordCVE-2026-31951

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-31951

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-31951

    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 wit

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.