CVE-2026-64655: GitHub CLI Attestation Verification Bypass via Unescaped Regex Metacharacters
Summary
CVE-2026-64655: GitHub CLI allows attestation verification bypass through unescaped regex metacharacters. Affects github.com/cli/cli/v2 versions < 2.97.0. Fixed in 2.97.0. How to fix ↓
Also tracked for
- github.com/cli/cli · Go
The same CVE-2026-64655 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
GitHub CLI is a command-line tool that allows users to interact with GitHub repositories and perform various tasks such as creating issues, managing pull requests, and verifying code signatures. It is widely used in CI/CD pipelines for automating workflows. However, a vulnerability has been discovered that affects the attestation verification process, potentially undermining the security of these automated workflows.
Vulnerability Detail
The vulnerability arises from the way GitHub CLI constructs regular expressions from user-supplied values in the --signer-repo and --signer-workflow flags. These values are interpolated into a regex pattern without escaping metacharacters, allowing malicious actors to create lookalike repository names that can bypass verification checks. This could lead to unauthorized access or manipulation of CI/CD pipelines that rely on these verification processes.
How To Fix
Latest published version: v2.103.0 as of 23 Oct 2026
go get github.com/cli/cli/v2@v2.103.0Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.97.0
This is the first release that contains the fix.
go get github.com/cli/cli/v2@v2.97.0Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can avoid using the --signer-repo or --signer-workflow flags and instead utilize the --repo or --owner flags, which perform exact string comparisons and are not affected by this vulnerability.
Conclusion
In summary, CVE-2026-64655 is a vulnerability in GitHub CLI that allows for attestation verification bypass due to unescaped regex metacharacters. Users are advised to upgrade to version 2.97.0 or later to mitigate this risk and ensure the integrity of their CI/CD processes.
See every vulnerability recorded for github.com/cli/cli/v2 →
FAQ
The vulnerability allows attackers to create lookalike repository names that can bypass attestation verification, potentially compromising the integrity of CI/CD pipelines.
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The CVSS score of this vulnerability is 2.1, indicating a low severity level.
Regex metacharacters are special characters in regular expressions that have specific meanings, such as . which matches any single character.
This vulnerability can undermine supply chain verification processes that rely on trusted signing workflows, allowing attackers to potentially introduce malicious code.
References
Related vulnerabilities
Recent vulnerabilities recorded for github.com/cli/cli/v2.
