Описание
sigstore-go has a multi-log threshold bypass via single compromised log
Impact
What kind of vulnerability is it? Who is impacted?
A verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) expected defense-in-depth against the compromise of a single log instance. However, threshold counting counted verified witnesses per-entry or per-validation-path rather than per-log-authority.
As a result, a single compromised transparency log could forge multiple entries with different indices, and a single compromised CT log could verify multiple times (either across multiple certificate chains or via multiple embedded SCTs), fully satisfying the multi-log threshold requirements and defeating the multi-log policy.
Note that this does not affect Cosign, as Cosign sets a threshold of 1.
Patches
Has the problem been patched? What versions should users upgrade to?
Upgrade to v1.1.5.
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
There is no workaround, beyond relying on trusted logs.
Ссылки
- https://github.com/sigstore/sigstore-go/security/advisories/GHSA-9vcr-p3rj-q5q6
- https://nvd.nist.gov/vuln/detail/CVE-2026-49834
- https://github.com/sigstore/sigstore-go/pull/633
- https://github.com/sigstore/sigstore-go/commit/dbb07e62623edd5b175fb9dd5a41dcb85a159207
- https://github.com/sigstore/sigstore-go/releases/tag/v1.2.0
Пакеты
github.com/sigstore/sigstore-go
<= 1.1.4
1.2.0
Связанные уязвимости
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.
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.
sigstore-go is a Go library for Sigstore signing and verification. Pri ...