CVE-2026-4276 in RAG API
Summary
by MITRE • 03/16/2026
LibreChat RAG API, version 0.7.0, contains a log-injection vulnerability that allows attackers to forge log entries.
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Analysis
by VulDB Data Team • 03/21/2026
The vulnerability identified as CVE-2026-4276 affects LibreChat RAG API version 0.7.0 and represents a critical log-injection flaw that enables malicious actors to manipulate system logging mechanisms. This vulnerability resides within the authentication and logging components of the application, specifically targeting how user inputs are processed and recorded in log files. The issue stems from insufficient input validation and sanitization of user-provided data that flows into the logging subsystem, creating an avenue for attackers to inject malicious content into log entries.
The technical implementation of this vulnerability allows an attacker to craft specially formatted input that, when processed by the RAG API, gets written to log files with embedded malicious content. This injection can occur through various user-facing interfaces such as authentication requests, API endpoints, or user input fields that are subsequently logged for audit purposes. The flaw typically manifests when user-supplied data containing special characters or control sequences is directly incorporated into log messages without proper sanitization or encoding. This creates opportunities for attackers to inject log entries that may contain malicious payloads, command sequences, or crafted content designed to manipulate log analysis tools or obscure legitimate activities.
The operational impact of this vulnerability extends beyond simple log manipulation, as it can significantly compromise the integrity and reliability of system audit trails and security monitoring processes. Attackers can exploit this weakness to hide their activities within legitimate-looking log entries, making detection and forensic analysis considerably more challenging. The compromised logging functionality can also be leveraged to create false positives in security monitoring systems or to inject content that might be interpreted by log analysis tools as malicious activity, potentially leading to misdirection of security teams. Additionally, the vulnerability may enable attackers to manipulate log-based access controls or authentication mechanisms that rely on log data for decision-making processes.
Security professionals should implement immediate mitigations including comprehensive input validation and sanitization of all user-supplied data before logging, proper encoding of special characters in log messages, and regular review of log entries for suspicious patterns. The vulnerability aligns with CWE-117, which addresses improper output neutralization for logs, and can be mapped to ATT&CK technique T1562.006 for "Impair Command History Logging" as it directly affects the integrity of system logging mechanisms. Organizations should also consider implementing log integrity monitoring solutions that can detect anomalous patterns in log entries and establish robust log management practices including regular log file integrity checks and secure log storage mechanisms. The remediation process should include code review to identify all logging points that might be vulnerable to injection attacks and implementation of secure logging frameworks that properly handle user input data.