3.7

CVE-2026-24122: Cosign Certificate Chain Expiry Validation Issue Allows Issuing Certificate Expiry to Be Overlooked

Analyzed
AliasesUBUNTU-CVE-2026-24122DEBIAN-CVE-2026-24122CGA-235h-6c7h-jcg6
Published 19-02-2026Last modified 20-02-2026

Vulnerability summary

CVE-2026-24122 is a low (CVSS 3.7) Improper Certificate Validation vulnerability in sigstore cosign. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 12% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 3.7, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
3.7/10
010
Low · v3.1 (CVE.org)
EPSS score
0.21%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 8 · Related 9
OPENSUSE-SU-2026:10235-1OPENSUSE-SU-2026:11676-1OPENSUSE-SU-2026:20386-1OPENSUSE-SU-2026:21483-1OPENSUSE-SU-2026:21801-1SUSE-SU-2026:0757-1

Timeline

  1. 19-02-2026
    PublishedVulnerability first disclosed.
  2. 20-02-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

12%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.21% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Cosign

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard128 products
  • aactl< 0.4.12-r59
  • cloudbeat-8.17< 8.17.10-r27
  • cloudbeat-8.19< 8.19.18-r0
  • cloudbeat-9.0< 9.0.8-r30
  • cloudbeat-9.1< 9.1.10-r24
Wolfi27 products
  • aactl< 0.4.12-r59
  • crossplane-2.1< 2.1.7-r4
  • ko< 0.19.0-r0
  • kyverno-1.16< 1.16.4-r12
  • kyverno-1.17All versions (No fix recorded) | < 1.17.2-r35
Github.com/sigstore/cosign2 products
  • v2All versions (No fix recorded)
  • v3< 3.0.5
Debian1 product
  • cosignAll versions (No fix recorded) | < 3.0.6-1
Github.com/sigstore1 product
  • cosign< 3.0.5 | All versions (No fix recorded)
Opensuse1 product
  • hauler&distro=openSUSE Tumbleweed< 1.4.2-1.1
Sigstore1 product
Ubuntu1 product
  • cosignAll versions (No fix recorded)

8 vendors · 162 products

References

10 links