vulnerability / NVI-00011988 / Revision 1
GitHub CLI allows attestation verification bypass through unescaped regex metacharacters
GitHub lists this reviewed advisory for github.com/cli/cli/v2. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
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02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/cli/cli/v2
source listed< 2.97.0
### Summary A security vulnerability has been identified in GitHub CLI that could allow attestation verification bypass when using `gh attestation verify` with `--signer-repo` or `--signer-workflow` flags. GitHub CLI builds the certificate matcher from these flag values without escaping regex metacharacters, so a repository or workflow name is treated as a regular expression rather than a literal string. GitHub permits characters such as `.` in organization, repository, and workflow path names, and `.` is a regex wildcard, so a malicious actor can create a lookalike name that satisfies a matcher intended for a different, trusted signer. ### Details GitHub CLI constructs a regular expression from the `--signer-repo` and `--signer-workflow` values and matches it against the signing certificate's SAN (Subject Alternative Name) during Sigstore attestation verification. The user-supplied value is interpolated into the pattern without escaping regex metacharacters, so any metacharacter permitted in a GitHub path is interpreted as regex syntax instead of a literal character. The most practical case is `.` , which GitHub allows in org/repo names and is a regex wildcard meaning
03 / Response
What to do next
- investigate
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-mm27-mwq9-fr5g ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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