What’s Vulnerable › Vulnerabilities

CVE-2026-23831: Rekor COSE v0.0.1 Canonicalize crashes when passed empty Message

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-22 · updated 2026-06-17
• Weakness: CWE-476

Description

Rekor is a software supply chain transparency log. In versions 1.4.3 and below, the entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message, causing nil Pointer Dereference. Function validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This issue has been fixed in version 1.5.0.

Affected products

• sigstore rekor: before 1.5.0 — fixed in 1.5.0

How to fix

Upgrade to a fixed version: sigstore rekor 1.5.0. Check the vendor advisory for mitigations.

References

• https://github.com/sigstore/rekor/commit/39bae3d192bce48ef4ef2cbd1788fb5770fee8cd
• https://github.com/sigstore/rekor/releases/tag/v1.5.0
• https://github.com/sigstore/rekor/security/advisories/GHSA-273p-m2cw-6833

Get alerted when CVE-2026-23831 or the next vulnerability affects your stack