CVE-2026-24122
Cosign Certificate Chain Expiry Validation Issue Allows Issuing Certificate Expiry to Be Overlooked
Description
Cosign provides code signing and transparency for containers and binaries. In versions 3.0.4 and below, an issuing certificate with a validity that expires before the leaf certificate will be considered valid during verification even if the provided timestamp would mean the issuing certificate should be considered expired. When verifying artifact signatures using a certificate, Cosign first verifies the certificate chain using the leaf certificate's "not before" timestamp and later checks expiry of the leaf certificate using either a signed timestamp provided by the Rekor transparency log or from a timestamp authority, or using the current time. The root and all issuing certificates are assumed to be valid during the leaf certificate's validity. There is no impact to users of the public Sigstore infrastructure. This may affect private deployments with customized PKIs. This issue has been fixed in version 3.0.5.
How to fix CVE-2026-24122
To remediate CVE-2026-24122, upgrade the affected package to a fixed version below.
- —upgrade to 3.0.5 or later
- —no fix listed
- —upgrade to 3.0.5 or later
- —no fix listed
- —no fix listed
- —upgrade to 3.0.5 or later
Is CVE-2026-24122 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (6)
- from 0, < 3.0.5
- from 0
- from 0, < 3.0.5
- from 0
- from 0
- from 0, < 3.0.5
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | LOW3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |