Security fixes go into the latest minor release line of pySigma. Older major versions are not patched.

Please do not open a public issue, discussion or pull request for a security problem.

Report it privately through GitHub: Security → Advisories → "Report a vulnerability" on this repository (https://github.com/SigmaHQ/pySigma/security/advisories/new). If you cannot use GitHub, contact one of the maintainers listed in pyproject.toml privately.

Please include:

• the affected component (rule parser, modifier, processing pipeline, conversion base class, plugin loader, …) and the pySigma version or commit;
• a minimal Sigma rule, pipeline or API call that reproduces the problem, with the observed and expected output;
• the impact you see (see the scope below) and, if you have one, a proposed fix.

pySigma turns Sigma rules and processing pipelines, which are often third-party or community content, into queries that run in a SIEM. The following are in scope:

• Code execution or file access: loading rules, pipelines or plugins that leads to code execution, unsafe deserialisation, path traversal, or writes outside the intended location.
• Denial of service: a small crafted rule or pipeline that causes excessive CPU or memory use (for example YAML alias expansion, or pathological regex or wildcard expansion).
• Plugin supply chain: flaws in plugin discovery or installation that could install or load unintended code.

Out of scope (report publicly as bugs):

• Query or configuration injection: Sigma rules are not a security layer and were never designed to prevent harmful effects from injected or malicious rule content in a target system. Manipulating query structures or backend configurations through crafted rules is not part of this project’s security scope. Users are responsible for ensuring that the rules they use are trustworthy, and any potential impact must be controlled through proper permissions and safeguards in the target system.
• Conversion errors that make a rule match more or fewer events than intended, without attacker-controlled input changing the query structure. These are important, but they are handled as normal issues and pull requests so fixes reach users quickly.
• A systemic and severe detection gap (for example a whole modifier class never matching) may be reported privately; the maintainers decide whether it becomes an advisory.

Report issues in backends or pipelines maintained in separate repositories to that repository. If the root cause is in pySigma, report it here.

• We credit reporters in the advisory unless they ask not to be credited.
• When a fix changes the behaviour of dependent SigmaHQ projects (sigma-cli, backends, pipelines), we may coordinate their releases.
• We ask reporters to keep details private until the advisory is published or 90 days have passed, whichever comes first, unless agreed otherwise.