GHSA-273p-m2cw-6833 is a medium-severity (CVSS 5.3) NULL Pointer Dereference vulnerability in github.com/sigstore/rekor. O3 Security confirms whether GHSA-273p-m2cw-6833 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Rekor's COSE v0.0.1 entry type nil pointer dereference in Canonicalize via empty Message
Real-World Exposure
github.com/sigstore/rekorReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sigstore/rekor | all versions | 1.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sigstore/rekor. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/sigstore/rekor to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-273p-m2cw-6833 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-273p-m2cw-6833 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-273p-m2cw-6833. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-273p-m2cw-6833 in your dependencies?
O3 detects GHSA-273p-m2cw-6833 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.