Missing Authentication for Critical Function in LibreChat - CVE-2026-54040
Published: June 3, 2026
Vulnerability identifier: #VU133264
CSH Severity: Low
CVSS v4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-54040
CWE-ID: CWE-306
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass two-factor authentication and disable two-factor authentication.
The vulnerability exists due to missing authentication for a critical function in the POST /api/auth/2fa/backup/regenerate endpoint when handling requests to regenerate backup codes. A remote user can send a crafted authenticated request using a stolen session token to bypass two-factor authentication and disable two-factor authentication.
The endpoint also returns newly generated plaintext backup codes and their hashes in the response.
Affected software
LibreChat
How to mitigate CVE-2026-54040
Install security update from vendor's website.
LibreChat - update to 0.8.4 rc1