CVE-2026-23831
Rekor's COSE v0.0.1 entry type nil pointer dereference in Canonicalize via empty Message in github.com/sigstore/rekor
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.
How to fix CVE-2026-23831
To remediate CVE-2026-23831, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 1.5.0 or later
- —upgrade to 1.5.0 or later
Is CVE-2026-23831 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0
- from 0, < 1.5.0
- from 0, < 1.5.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |