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CRITICAL severity

CVE-2021-38197 — go-unarr

CRITICALFix: gen2brain/go-unarr@239ec40

CVE-2021-38197 is a critical-severity (CVSS 9.8) Path Traversal vulnerability in github.com/gen2brain/go-unarr. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/gen2brain/go-unarr — see the affected versions and patch details below.

Tarslip in go-unarr

Also known asGHSA-v9j4-cp63-qv62GO-2022-0929
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs81th percentile — riskier than 81% of all scored CVEsHighest risk
0.37%1.12%1.86%2.61%0.9%2.1%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-38197 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 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/gen2brain/go-unarr

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

unarr.go in go-unarr (aka Go bindings for unarr) 0.1.1 allows Directory Traversal via ../ in a pathname within a TAR archive.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/gen2brain/go-unarrall versions0.1.4go get github.com/gen2brain/go-unarr@v0.1.4

Affected Products

1 product · 1 configurations
Application
go-unarrgo-unarr_project
1 version
0.1.1
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

unarr.go in go-unarr (aka Go bindings for unarr) 0.1.1 allows Directory …

github.comNVDAug 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gen2brain/go-unarr, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/gen2brain/go-unarr to 0.1.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-38197 is resolved across your whole dependency graph.

  3. 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

unarr.go in go-unarr (aka Go bindings for unarr) 0.1.1 allows Directory Traversal via ../ in a pathname within a TAR archive.
O3 Security · Impact-Aware SCA

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CVE-2021-38197: go-unarr Path Traversal — Fixed in 0.1.4