GitHub CLI (gh) is GitHub’s official command line tool. Prior to 2.97.0, gh attestation verify builds the certificate Subject Alternative Name matcher from the –signer-repo and –signer-workflow flag values without escaping regex metacharacters, so a user-supplied repository or workflow name is treated as a regular expression rather than a literal string. Because GitHub permits characters such as . in organization, repository, and workflow path names and . is a regex wildcard, an attacker can register a lookalike name (for example github/artifact.attestations-workflows) that satisfies a matcher intended for a different trusted signer (github/artifact-attestations-workflows), bypassing the intended Sigstore attestation verification. Exploitation requires the attacker to create a plausible lookalike repository and produce valid attestations from it, which could undermine supply chain verification for CI/CD pipelines or policy gates that pin trust to a specific signing workflow. This issue is fixed in version 2.97.0.
Weakness
The product specifies a regular expression in a way that causes data to be improperly matched or compared.
Potential Mitigations
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/15.html
- https://cwe.mitre.org/data/definitions/6.html
- https://cwe.mitre.org/data/definitions/79.html