CVE-2021-21272

Zip slip directory exploit in github.com/deislabs/oras

Workarounds

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.

References

• Zip Slip

For more information

If you have any questions or comments about this advisory:

• Open an issue on the GitHub repo
• Email the list of maintainers

The directory support (#55) 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.

Precisely, the following users of the affected versions are impacted

• oras CLI users who runs oras pull.
• Go programs, which invokes github.com/deislabs/oras/pkg/content.FileStore.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2021-21272 has a CVSS score of 7.7 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.0); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

The problem has been patched by the PR linked with this advisory. Users should upgrade their oras CLI and packages to 0.9.0.

1. What is CVE-2021-21272? CVE-2021-21272 is a high-severity path traversal vulnerability in github.com/deislabs/oras (go), affecting versions < 0.9.0. It is fixed in 0.9.0. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2021-21272? CVE-2021-21272 has a CVSS score of 7.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/deislabs/oras are affected by CVE-2021-21272? github.com/deislabs/oras (go) versions < 0.9.0 is affected.
4. Is there a fix for CVE-2021-21272? Yes. CVE-2021-21272 is fixed in 0.9.0. Upgrade to this version or later.
5. Is CVE-2021-21272 exploitable, and should I be worried? Whether CVE-2021-21272 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-21272 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-21272? Upgrade github.com/deislabs/oras to 0.9.0 or later.