CVE-2026-103090Unauthenticated Biscuit Credential Disclosure via GET /enroll/status in Google OSS Agent Mesh (SAM)

Official description

Missing Authentication for Critical Function (CWE-306) and Insufficiently Protected Credentials (CWE-522) in the control plane enrollment status handler (HandleEnrollStatus at GET /enroll/status in internal/controlplane/server.go) in Google OSS Agent Mesh (SAM) versions 0.1.0-alpha.1 through 0.1.0-alpha.8 allow an unauthenticated remote attacker to retrieve an approved bootstrap-enrolled peer's signed Biscuit identity token by supplying a peer_id obtainable from the unauthenticated GET /info endpoint. A related flaw in POST /enroll allowed any bootstrap-token holder to re-fetch another peer's credential. An attacker can replay the disclosed Biscuit token as a bearer credential on /policies to read mesh authorization policies and on /routers/lease to overwrite advertised router multiaddrs. Users should upgrade to version 0.1.0-alpha.9 or later, which requires cryptographic proof of possession of the enrollment private key on credential-releasing endpoints, enforces rate limiting, and validates router lease addresses.

Affected products (as reported)

References

• https://github.com/google/sam/security/advisories/GHSA-hp3x-79wr-rx66 vendor-advisory
• https://github.com/google/sam/releases/tag/v0.1.0-alpha.9 release-notes
• https://github.com/google/agentmesh/security/advisories/GHSA-hp3x-79wr-rx66 exploit