CVE-2026-23831 Rekor COSE v0.0.1 Canonicalize crashes when passed empty Message
An attacker can cause a panic in Rekor by submitting a malformed COSE entry with an empty message, resulting in a temporary service disruption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23831?
CVE-2026-23831 is a medium-severity vulnerability in sigstore rekor, published on 22 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-476
Which versions are affected by CVE-2026-23831?
3 open source packages ship an affected version, including github.com/sigstore/rekor. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/sigstore/rekor Go | All versions | 1.5.0 |
github.com/sigstore/rekor Go | All versions | 1.5.0 |
github.com/sigstore/rekor Go | All versions | 1.5.0 |
Products include Linuxfoundation Rekor.
How do I fix CVE-2026-23831?
Upgrade github.com/sigstore/rekor to 1.5.0 or later.
Is CVE-2026-23831 being exploited?
There is no known exploitation of CVE-2026-23831 in the wild and no public exploit code.
Other vulnerabilities in sigstore rekor
Sources
Also known as CLEANSTART-2026-DO33187, CLEANSTART-2026-RI42866, DEBIAN-CVE-2026-23831, GHSA-273p-m2cw-6833, GO-2026-4354, MINI-299f-xvhq-vgpp and 23 more.