Bug 2477935 (CVE-2026-44310)

Summary:	CVE-2026-44310 github.com/sigstore/gitsign: Gitsign: Security bypass in commit verification
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	eborisov, lball, ngough, veshanka
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Gitsign, a tool used for signing Git commits with a GitHub or OIDC (OpenID Connect) identity. A remote attacker could craft a specially designed signed message that contains an empty certificate set. This malformed message would cause Gitsign's verification process to silently fail, leading to a critical security bypass. Consequently, systems relying on Gitsign for commit verification might incorrectly interpret unverified or malicious commits as legitimate, undermining the integrity of the commit history.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-05-15 17:01:29 UTC

Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. From 0.4.0 to before 0.15.0, CertVerifier.Verify() in pkg/git/verifier.go unconditionally dereferences certs[0] after sd.GetCertificates() without checking the slice length. A CMS/PKCS7 signed message with an empty certificate set is a structurally valid DER payload; GetCertificates() returns an empty slice with no error, causing an immediate index-out-of-range panic. On the gitsign --verify code path (the GPG-compatible mode invoked by git verify-commit), the panic is silently recovered by internal/io/streams.go's Wrap() function, which returns nil instead of an error. main.go then exits with code 0, causing exit-code-only verification callers to interpret the failed verification as success. This vulnerability is fixed in 0.15.0.