Do not open a public issue for security vulnerabilities.

Report vulnerabilities privately via GitHub Security Advisories.

Include:

• A description of the vulnerability and its potential impact
• Steps to reproduce (minimal reproducer preferred)
• Affected versions

You will receive an acknowledgement within 48 hours and a status update within 7 days.

pyperfguard is a static analysis and runtime instrumentation tool. Security considerations specific to this project:

• Untrusted source files: pyperfguard parses Python source via ast.parse() (no eval, no exec, no code execution of analyzed files). Parsing an adversarially crafted .py file is safe — worst case is a SyntaxError that is caught and logged.
• Plugin loading: Rules/reporters/patchers loaded via importlib.metadata entry points execute arbitrary code from installed packages. Only install packages you trust.

• Monkey-patching: The runtime engine patches driver internals at the module level. If an attacker can influence which patchers are loaded, they can intercept DB calls. Use [tool.pyperfguard.runtime] enabled = false (default) in untrusted environments.
• Bootstrap / sitecustomize: pyperfguard bootstrap install appends a snippet to sitecustomize.py, which runs on every Python startup for that environment. Only run this command in controlled environments. The snippet is guarded by the PYPERFGUARD_AUTO environment variable.
• Event buffer: The runtime Scope event buffer is capped at 10,000 events (deque(maxlen=10_000)). There is no network egress; events are in-process only.

• pyproject.toml is parsed with tomllib (stdlib). A malformed file emits a UserWarning and falls back to defaults — it is never executed.
• Config.exclude patterns use fnmatch, not shell expansion. No shell execution occurs.

• Issues in third-party packages that pyperfguard instruments (SQLAlchemy, Cassandra driver, etc.)
• Denial of service via extremely large source files (pyperfguard is a dev/CI tool, not a server)
• Theoretical timing attacks on the event fingerprinting logic