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GHSA-xhcr-cqfr-m3hv

GHSA-xhcr-cqfr-m3hv is a remote code execution vulnerability in atomic-agents-stack. O3 Security confirms whether GHSA-xhcr-cqfr-m3hv is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

atomic-agents-stack: HTTP MCP catalog accepts cleartext http and spawns catalog-supplied commands (MITM to RCE)

Published
Aug 17, 2026
Updated
Aug 17, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Aug 17, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🐍atomic-agents-stack

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

The HTTP MCP server-registry backend factory (atomic_agents/mcp_registry/http.py, make_http_mcp_server_registry_backend_from_url) accepts both http and https schemes. Catalog entries carry command/args that are type-validated but content-unrestricted, and are later spawned as local stdio subprocesses by MCPClientPool. Over a cleartext http:// catalog URL, a network man-in-the-middle can rewrite the catalog response to inject an arbitrary command/args and obtain code execution on the agent host, with no LLM involvement. The Policy MCP allowlist is not a default mitigation (mcp_allow_fn defaults to None), so absent an operator-authored allowlist every resolved spec connects.

Affected: mcp_registry/http.py, all versions through 1.0.0. (The https path is sound: httpx defaults to verify=True, follow_redirects=False.)

Fix: require https by default and gate http:// behind a loud explicit opt-in. Defense-in-depth: allowlist the resolved command basename (or require confirmation) before any registry-sourced subprocess spawn. Document the consequence in spec/36.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIatomic-agents-stackall versions1.1.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for atomic-agents-stack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update atomic-agents-stack to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xhcr-cqfr-m3hv is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-xhcr-cqfr-m3hv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-xhcr-cqfr-m3hv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

The HTTP MCP server-registry backend factory (`atomic_agents/mcp_registry/http.py`, `make_http_mcp_server_registry_backend_from_url`) accepts both `http` and `https` schemes. Catalog entries carry `command`/`args` that are type-validated but content-unrestricted, and are later spawned as local stdio subprocesses by `MCPClientPool`. Over a cleartext `http://` catalog URL, a network man-in-the-middle can rewrite the catalog response to inject an arbitrary `command`/`args` and obtain code execution on the agent host, with no LLM involvement. The Policy MCP allowlist is not a default mitigation (`
O3 Security · Impact-Aware SCA

Is GHSA-xhcr-cqfr-m3hv in your dependencies?

O3 detects GHSA-xhcr-cqfr-m3hv across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.