Authentication Bypass in Headroom's LLM Proxy Affects Multiple Deployments

CVE-2026-77776

What is CVE-2026-77776?

Headroom's LLM proxy contains a significant flaw in how it handles the x-headroom-user-id request header, which can be exploited to bypass authentication controls. Specifically, this vulnerability arises from the proxy deriving the memory owner directly from this header without proper validation. An attacker can impersonate another user by submitting their identifier, potentially gaining unauthorized access to stored data in the LLM memory. The recent update aims to resolve this issue by introducing a new identity binding mechanism that mitigates the risk of unauthorized access. However, some deployment configurations may still expose sensitive data due to lax security measures. Thus, it is crucial for users to review their deployment settings to ensure appropriate authentication measures are in place.

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