Teknium ba4357d13b fix(env_passthrough): reject Hermes provider credentials from skill passthrough (#13523) ...

A skill declaring `required_environment_variables: [ANTHROPIC_TOKEN]` in
its SKILL.md frontmatter silently bypassed the `execute_code` sandbox's
credential-scrubbing guarantee. `register_env_passthrough` had no
blocklist, so any name a skill chose flipped `is_env_passthrough(name) =>
True`, which shortcircuits the sandbox's secret filter.

Fix: reject registration when the name appears in
`_HERMES_PROVIDER_ENV_BLOCKLIST` (the canonical list of Hermes-managed
credentials — provider keys, gateway tokens, etc.). Log a warning naming
GHSA-rhgp-j443-p4rf so operators see the rejection in logs.

Non-Hermes third-party API keys (TENOR_API_KEY for gif-search,
NOTION_TOKEN for notion skills, etc.) remain legitimately registerable —
they were never in the sandbox scrub list in the first place.

Tests: 16 -> 17 passing. Two old tests that documented the bypass
(`test_passthrough_allows_blocklisted_var`, `test_make_run_env_passthrough`)
are rewritten to assert the new fail-closed behavior. New
`test_non_hermes_api_key_still_registerable` locks in that legitimate
third-party keys are unaffected.

Reported in GHSA-rhgp-j443-p4rf by @q1uf3ng. Hardening; not CVE-worthy
on its own per the decision matrix (attacker must already have operator
consent to install a malicious skill).

2026-04-21 06:14:25 -07:00

5.4 KiB

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