Rekor's COSE v0.0.1 entry type nil pointer dereference in Canonicalize via empty Message

CVE-2026-23831 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Summary

Rekor’s cose v0.0.1 entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message. validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload.

Impact

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.

Patches

Upgrade to v1.5.0

Workarounds

None

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-01-22 18:41:23 UTC
Updated
2026-01-23 15:46:18 UTC
GitHub reviewed
2026-01-22 18:41:23 UTC
NVD published
2026-01-22

EPSS Score

Score Percentile
0.02% 3.58%

CVSS Scores

Base score Version Severity Vector
5.3 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.

Identifiers

Type Value
GHSA GHSA-273p-m2cw-6833 ↗
CVE CVE-2026-23831 ↗

CWEs

CWE id Name
CWE-476 NULL Pointer Dereference

Credits

  • 1seal (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
go github.com/sigstore/rekor <= 1.4.3 1.5.0 —

References

cvelogic Threat Intelligence