CVE-2026-23831 MEDIUM

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

Vendor Sigstore
Product rekor
Weakness CWE-476
Published January 22, 2026
Last update January 23, 2026

CVSS base score

5.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

January 22, 2026 CVE published
January 23, 2026 Record updated