HighVulnerability

CVE-2026-31945: LibreChat server-side request forgery in agent actions and MCP

Source: NVD(opens in a new tab)
Identifier: CVE-2026-31945
Published: March 27, 2026
Record updated: October 9, 2026

Known exploitation: Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS: 0.3%

Summary

LibreChat versions 0.8.2-rc2 through 0.8.2 are vulnerable to server-side request forgery (SSRF) when agent actions or MCP are used. The earlier fix for GHSA-rgjq-4q58-m3q8 added hostname validation but does not check whether DNS resolution yields a private IP address, so an attacker can bypass it and reach internal resources such as an internal RAG API or cloud instance metadata endpoints.

Mitigation

Version 0.8.3-rc1 contains a patch.

Details

Scores and exploitation

CVSS score: 7.7(high)
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Attack vector: network
Attack complexity: low
Privileges required: low
User interaction: none
EPSS: 0.3%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on November 9, 2026.
Disclosure date: March 27, 2026

Weaknesses and techniques

Weakness (CWE): CWE-918
Attack pattern (CAPEC): CAPEC-664

Classification

Attack type: Other
Attack sophistication: Moderate
AI component targeted: Plugin
Impact: Confidentiality
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative. The source gives this advisory a description and no title, so the title above is a headline generated from the source text.

Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-31945

First tracked: March 28, 2026 at 02:07 AM ET, from NVD/CVE Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 90% (self-assessed)

Summary

Mitigation

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