How severe is CVE-2021-21272?

CVE-2021-21272 has a CVSS score of 7.7/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-21272?

CVE-2021-21272 affects the following packages: github.com/deislabs/oras (Go). Ecosystems affected: Go.

How do I fix CVE-2021-21272?

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.

How do I detect CVE-2021-21272 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/deislabs/oras, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-21272 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2021-21272 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21272 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-21272?

CVE-2021-21272 has an EPSS (Exploit Prediction Scoring System) score of 1.4%, placing it in the 73th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-21272?

CVE-2021-21272 is classified as Path Traversal (CWE-22), CWE-59 (CWE-59). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-21272 published, and has it been updated?

CVE-2021-21272 was published on January 25, 2021 and was last updated on August 27, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

HIGH severity

CVE-2021-21272 — oras

HIGHFix: deislabs/oras@96cd904

CVE-2021-21272 is a high-severity (CVSS 7.7) Path Traversal vulnerability in github.com/deislabs/oras. A fix is available for github.com/deislabs/oras — see the affected versions and patch details below.

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

Also known asBIT-oras-2021-21272GHSA-g5v4-5x39-vwhxGO-2021-0099

Published

Jan 25, 2021

Updated

Aug 27, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs73th percentile — riskier than 73% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-21272 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐹github.com/deislabs/oras

Real-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

Impact

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.

Patches

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

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

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/deislabs/oras`	all versions	0.9.0`go get github.com/deislabs/oras@v0.9.0`

Affected Products

1 product · 1 configurations

Application

orasdeislabs

≥ 0.4.0 && < 0.9.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/deislabs/oras, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

### Impact 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 `githu