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Luu, T.J.

GHSA-5mwj-v5jw-5c97: LobeHub: Unauthenticated authentication bypass on `webapi` routes via forgeable `X-lobe-chat-auth` header

mediumvulnerability

security

Source: GitHub Advisory DatabaseApril 8, 2026CVE-2026-39411

Summary

LobeHub's webapi routes use a client-controlled header called `X-lobe-chat-auth` for authentication, but it's only XOR-obfuscated (a simple reversible encoding) with a hardcoded key that's visible in the code. An attacker can forge this header to bypass authentication and access protected routes like chat, model listing, and image generation without logging in, potentially using the server's API credentials or impersonating other users.

Solution / Mitigation

Update to LobeHub version 2.1.48 or later, which patches this vulnerability. According to the advisory, the fix involves: stopping use of `X-lobe-chat-auth` as an authentication token, removing the simple apiKey truthiness check as an auth decision, and requiring a real server-validated session, OIDC token (a standard authentication protocol), or validated API key for all protected webapi routes. If client payloads are still needed, they should be signed server-side with an HMAC (a cryptographic signature) or replaced with a normal session-bound backend lookup.