Improper Certificate Validation Affecting github.com/sigstore/cosign/pkg/cosign package, versions <3.0.5
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMSIGSTORECOSIGNPKGCOSIGN-15323169
- published20 Feb 2026
- disclosed19 Feb 2026
- credit1seal
Introduced: 19 Feb 2026
CVE-2026-24122 Â (opens in a new tab)How to fix?
Upgrade github.com/sigstore/cosign/pkg/cosign to version 3.0.5 or higher.
Overview
Affected versions of this package are vulnerable to Improper Certificate Validation due to improper validation of certificate chains during signature verification when transparency log verification is skipped. An attacker can cause acceptance of signatures with expired intermediate certificates by providing a certificate chain where the intermediate certificate has expired before the leaf certificate, potentially allowing unauthorized signature validation.
Note:
No impact to users of the public Sigstore infrastructure. This may affect private deployments with customized PKIs. In practice, this is unlikely to occur as CAs should not be issuing certificates that outlive the validity of the CA and its parents.