What’s Vulnerable › Vulnerabilities

CVE-2026-49834: sigstore-go: Multi-log threshold bypass via single compromised log

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-17 · updated 2026-10-24
• Weakness: CWE-347

Description

sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.0, a verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) counts verified witnesses per entry or per validation path rather than per log authority, allowing a single compromised transparency log or CT log to satisfy multi-log threshold requirements and defeat the multi-log policy. This issue is fixed in version 1.2.0.

Affected products

• sigstore-go: before 1.2.0 — fixed in 1.2.0

How to fix

Upgrade to a fixed version: sigstore-go 1.2.0. Check the vendor advisory for mitigations.

References

• https://github.com/sigstore/sigstore-go/commit/dbb07e62623edd5b175fb9dd5a41dcb85a159207
• https://github.com/sigstore/sigstore-go/pull/633
• https://github.com/sigstore/sigstore-go/releases/tag/v1.2.0
• https://github.com/sigstore/sigstore-go/security/advisories/GHSA-9vcr-p3rj-q5q6

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