GitHub CLI allows attestation verification bypass through unescaped regex metacharacters

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

• github.com/cli/cli/v2 2.97.0Fixed version · GitHub Advisories · go package github.com/cli/cli/v2: upgrade to 2.97.0 or later (affected < 2.97.0)

[ Packages ]Affected open-source packages

• github.com/cli/cli/v2 goAffected < 2.97.0 · fixed in 2.97.0 · GHSA-mm27-mwq9-fr5g

[ References ]References

• github.com/cli/cli/security/advisories/GHSA-mm27-mwq9-fr5gx_refsource_CONFIRM
• github.com/cli/cli/commit/55dbb4dc6b7edb10b48e3d7fc5bccd32318d1b55x_refsource_MISC
• github.com/cli/cli/releases/tag/v2.97.0x_refsource_MISC