Gitsign is a keyless Sigstore to signing tool for Git commits with your a
GitHub / OIDC identity. gitsign may select the wrong Rekor entry to use during
online verification when multiple entries are returned by the log. gitsign uses
Rekor's search API to fetch entries that apply to a signature being verified.
The parameters used for the search are the public key and the payload. The
search API returns entries that match either condition rather than both. When
gitsign's credential cache is used, there can be multiple entries that use the
same ephemeral keypair / signing certificate. As gitsign assumes both
conditions are matched by Rekor, there is no additional validation that the
entry's hash matches the payload being verified, meaning that the wrong entry
can be used to successfully pass verification. Impact is minimal as while
gitsign does not match the payload against the entry, it does ensure that the
certificate matches. This would need to be exploited during the certificate
validity window (10 minutes) by the key holder.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-51746
https://www.cve.org/CVERecord?id=CVE-2024-51746
https://github.com/sigstore/gitsign/security/advisories/GHSA-8pmp-678w-c8xx
https://bugzilla.redhat.com/show_bug.cgi?id=2323965