Cyber Resilience

CVE-2026-4276

HighRCEUpdated

Published: 16 March 2026

Published
16 March 2026
Modified
05 June 2026
KEV Added
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Patch
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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0014 34.1th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-4276 is a high-severity Code Injection (CWE-94) vulnerability in Librechat Librechat. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 34.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as LLM Application Platforms; in the Other ATLAS/OWASP Terms risk domain.

The strongest mitigations our analysis identified are NIST 800-53 AU-9 (Protection of Audit Information) and SI-10 (Information Input Validation).

Deeper analysis

CVE-2026-4276 is a log-injection vulnerability affecting the LibreChat RAG API in version 0.7.0. Published on 2026-03-16, the flaw enables attackers to forge log entries. It carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N), indicating high severity primarily due to its impact on integrity.

Unauthenticated remote attackers can exploit this vulnerability over the network with low attack complexity and no user interaction. Exploitation allows forging log entries, which can mislead security monitoring, incident response, or forensic analysis by injecting false data into logs.

Mitigation guidance is available in the CERT vulnerability note at https://kb.cert.org/vuls/id/624941.

EU & UK References

Vulnerability details

LibreChat RAG API, version 0.7.0, contains a log-injection vulnerability that allows attackers to forge log entries.

CWE(s)
CWE-94

AI Security AnalysisAI

AI Category
LLM Application Platforms
Risk Domain
Other ATLAS/OWASP Terms
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: librechat

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1565.001 Stored Data Manipulation Impact
Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data.
attack.mitre.org →
Why these techniques?

Log injection vuln in public-facing RAG API directly enables remote exploitation via T1190 and achieves stored log data manipulation (T1565.001) to falsify entries and mislead monitoring/forensics.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2025-69220Same product: Librechat Librechat
CVE-2025-41258Same product: Librechat Librechat
CVE-2025-69222Same product: Librechat Librechat
CVE-2026-31943Same product: Librechat Librechat
CVE-2026-33265Same product: Librechat Librechat
CVE-2024-10361Same product: Librechat Librechat
CVE-2026-22252Same product: Librechat Librechat
CVE-2026-31944Same product: Librechat Librechat
CVE-2026-31945Same product: Librechat Librechat
CVE-2026-31942Same product: Librechat Librechat

Affected Assets

librechat
librechat
0.7.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match
prevent

Directly prevents log-injection by validating and sanitizing user inputs to the LibreChat RAG API before they are logged.

AU-9 Protection of Audit Information good match
prevent

Protects audit information from unauthorized modification, comprehensively mitigating the forging of log entries.

AU-6 Audit Record Review, Analysis, and Reporting partial match
detect

Enables review and analysis of audit records to identify forged or anomalous log entries introduced by the vulnerability.

References