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CVE-2026-48791 sigstore CVE debrief

A vulnerability in sigstore-java, a Java client for interacting with sigstore infrastructure, was found in version 2.0.0. This version erroneously removed verification of the integrated time against the Fulcio certificate. The issue is fixed in version 2.1.0. Users verifying bundles with `dev.sigstore:sigstore-java:2.0.0` are impacted. To protect themselves, users can re-verify their artifacts using the newest sigstore-java or another current sigstore client. Transparency logs may also be audited for unauthorized signatures for a suspected reused identity.

Vendor
sigstore
Product
sigstore-java
CVSS
LOW 2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-13
Original CVE updated
2026-09-09
Advisory published
2026-08-13
Advisory updated
2026-09-09

Who should care

Defenders and users of sigstore-java version 2.0.0 should verify artifact signatures using the latest sigstore-java version to prevent potential security risks. Operators, platform administrators, vulnerability management teams, and security teams may be impacted by this vulnerability and should review their systems for affected deployments.

Why it matters

The vulnerability in sigstore-java version 2.0.0 requires verification of artifact signatures using the latest sigstore-java version to prevent potential security risks. Defenders and users of sigstore-java version 2.0.0 should take action to protect themselves.

  • Verification of artifact signatures may be required to prevent potential reuse of old Fulcio certificates
  • Audit of transparency logs may be necessary for unauthorized signatures

Technical summary

The sigstore-java client for interacting with sigstore infrastructure had a vulnerability in version 2.0.0 where it erroneously removed verification of the integrated time against the Fulcio certificate. This issue was fixed in version 2.1.0 with enhancements adhering to the Sigstore verification spec. The vulnerability impacts users verifying bundles with `dev.sigstore:sigstore-java:2.0.0`. Affected product deployments should be reviewed for potential security risks. Defenders should prioritize verifying artifact signatures using the latest sigstore-java version.

Defensive priority

Defenders should prioritize verifying artifact signatures using the latest sigstore-java version to prevent potential reuse of old Fulcio certificates.

Recommended defensive actions

  • Verify artifact signatures using the latest sigstore-java version
  • Audit transparency logs for unauthorized signatures
  • Update sigstore-java to version 2.1.0 or later
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in sigstore-java version 2.0.0 and its fix in version 2.1.0. Evidence limits are based on available information. Defenders should verify artifact signatures using the latest sigstore-java version to prevent potential reuse of old Fulcio certificates. The vulnerability impacts users verifying bundles with `dev.sigstore:sigstore-java:2.0.0`.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-48791 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-48791

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-48791 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-48791

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.