CVE-2021-21272 is a high-severity (CVSS 7.7) Path Traversal vulnerability in github.com/deislabs/oras. O3 Security confirms whether CVE-2021-21272 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Zip slip directory exploit in github.com/deislabs/oras
Real-World Exposure
github.com/deislabs/orasReal-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
ORAS is open source software which enables a way to push OCI Artifacts to OCI Conformant registries. ORAS is both a CLI for initial testing and a Go Module. In ORAS from version 0.4.0 and before version 0.9.0, there is a "zip-slip" vulnerability. The directory support feature allows the downloaded gzipped tarballs to be automatically extracted to the user-specified directory where the tarball can have symbolic links and hard links. A well-crafted tarball or tarballs allow malicious artifact providers linking, writing, or overwriting specific files on the host filesystem outside of the user-specified directory unexpectedly with the same permissions as the user who runs oras pull. Users of the affected versions are impacted if they are oras CLI users who runs oras pull, or if they are Go programs, which invoke github.com/deislabs/oras/pkg/content.FileStore. The problem has been fixed in version 0.9.0. For oras CLI users, there is no workarounds other than pulling from a trusted artifact provider. For oras package users, the workaround is to not use github.com/deislabs/oras/pkg/content.FileStore, and use other content stores instead, or pull from a trusted artifact provider.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/deislabs/oras | all versions | 0.9.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/deislabs/oras. 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/deislabs/oras to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21272 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-2021-21272 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-2021-21272. 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-2021-21272 in your dependencies?
O3 detects CVE-2021-21272 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.