Vulnerability · Published Feb 19, 2026 · Assigned by GitHub_M
CVE-2026-24122Cosign Certificate Chain Expiry Validation Issue Allows Issuing Certificate Expiry to Be Overlooked
Low 3.7
In plain English
A low-severity improper certificate validation in cosign from sigstore. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | cosign | no fix listed | DEBIAN-CVE-2026-24122 |
| Debian:14 | cosign | 3.0.6-1 | DEBIAN-CVE-2026-24122 |
| Go | github.com/sigstore/cosign | 3.0.5 | GHSA-wfqv-66vq-46rm |
| Go | github.com/sigstore/cosign | no fix listed | GO-2026-4529 |
| Go | github.com/sigstore/cosign/v2 | no fix listed | GO-2026-4529 |
| Go | github.com/sigstore/cosign/v3 | 3.0.5 | GO-2026-4529 |
| Ubuntu:25.10 | cosign | no fix listed | UBUNTU-CVE-2026-24122 |
| Ubuntu:26.10 | cosign | no fix listed | UBUNTU-CVE-2026-24122 |
Affected products (as reported)
Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- https://github.com/sigstore/cosign/security/advisories/GHSA-wfqv-66vq-46rm x_refsource_CONFIRM
- https://github.com/sigstore/cosign/commit/3c9a7363f563db76d78e2de2cabd945450f3781e x_refsource_MISC
- https://github.com/sigstore/cosign/releases/tag/v3.0.5 x_refsource_MISC