CVE-2026-24137 is a medium-severity (CVSS 5.8) Path Traversal vulnerability in github.com/sigstore/sigstore. O3 Security confirms whether CVE-2026-24137 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
sigstore legacy TUF client allows for arbitrary file writes with target cache path traversal
Real-World Exposure
github.com/sigstore/sigstoreReal-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
sigstore framework is a common go library shared across sigstore services and clients. In versions 1.10.3 and below, the legacy TUF client (pkg/tuf/client.go) supports caching target files to disk. It constructs a filesystem path by joining a cache base directory with a target name sourced from signed target metadata; however, it does not validate that the resulting path stays within the cache base directory. A malicious TUF repository can trigger arbitrary file overwriting, limited to the permissions that the calling process has. Note that this should only affect clients that are directly using the TUF client in sigstore/sigstore or are using an older version of Cosign. Public Sigstore deployment users are unaffected, as TUF metadata is validated by a quorum of trusted collaborators. This issue has been fixed in version 1.10.4. As a workaround, users can disable disk caching for the legacy client by setting SIGSTORE_NO_CACHE=true in the environment, migrate to https://github.com/sigstore/sigstore-go/tree/main/pkg/tuf, or upgrade to the latest sigstore/sigstore release.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sigstore/sigstore | all versions | 1.10.4 |
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/sigstore. 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/sigstore to 1.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-24137 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 CVE-2026-24137 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 CVE-2026-24137. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-24137 in your dependencies?
O3 detects CVE-2026-24137 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.