CVE-2026-84809: Tencent AI-Infra-Guard skill-scan Analysis Bypass via Excluded Python Bytecode
Tencent AI-Infra-Guard's skill-scan component excludes compiled Python bytecode files from analysis by hardcoding pycache directories and .pyc/.pyo/.pyd extensions into skip lists across multiple scanning surfaces. Attackers can distribute skills with benign Python source files alongside malicious compiled bytecode that executes on import while the scanner reports a safe verdict, enabling code execution when operators install the skill.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Do not hardcode __pycache__ directories and .pyc/.pyo/.pyd extensions into skip lists for skill-scan analysis; include compiled Python bytecode in scanning so import-executed bytecode cannot bypass the safe verdict.
Tencent AI-Infra-Guard skill-scan Excluded paths/extensions = __pycache__ and .pyc/.pyo/.pyd
Event History
Frequently Asked Questions
Who is exposed to this issue?
Operators who use skill-scan to assess skills before installing them are exposed if a skill can include compiled Python bytecode. The risk materializes when an operator installs a skill that skill-scan reported as safe and the malicious bytecode is imported.
What does an attacker need to exploit it?
An attacker needs to distribute a skill containing malicious compiled Python bytecode, such as files in __pycache__ directories or with .pyc, .pyo, or .pyd extensions. The skill can include benign-looking Python source while the bytecode executes when imported.
Are default scan exclusions involved?
Yes. The bypass results from hardcoded skip lists that exclude __pycache__ directories and .pyc, .pyo, and .pyd file extensions across multiple scanning surfaces.
How can I determine whether a scanned skill may have bypassed analysis?
Inspect the skill package for __pycache__ directories and files ending in .pyc, .pyo, or .pyd. A safe skill-scan verdict does not indicate that those excluded bytecode files were analyzed.