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Vulnerability · Published Jan 22, 2026 · Assigned by GitHub_M

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

Medium 5.3

In plain English

A medium-severity null pointer dereference in rekor from sigstore. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.4%top 63.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13rekorno fix listedDEBIAN-CVE-2026-23831
Debian:14rekor1.5.0-1DEBIAN-CVE-2026-23831
Gogithub.com/sigstore/rekor1.5.0GHSA-273p-m2cw-6833
Gogithub.com/sigstore/rekor1.5.0GO-2026-4354
Ubuntu:25.10rekorno fix listedUBUNTU-CVE-2026-23831
Ubuntu:26.10rekorno fix listedUBUNTU-CVE-2026-23831

Affected products (as reported)

VendorProductVersions
sigstore rekor < 1.5.0

Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References