How severe is CVE-2021-29482?

CVE-2021-29482 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-29482?

CVE-2021-29482 affects the following packages: github.com/ulikunitz/xz (Go). Ecosystems affected: Go.

How do I fix CVE-2021-29482?

Update github.com/ulikunitz/xz to 0.5.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29482 is resolved across your whole dependency graph.

How do I detect CVE-2021-29482 in my Go dependencies?

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

How do I mitigate CVE-2021-29482 if there is no patch (or I can't update yet)?

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.

Is CVE-2021-29482 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-29482 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-2021-29482?

CVE-2021-29482 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-2021-29482?

CVE-2021-29482 is classified as CWE-835 (CWE-835). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-29482 published, and has it been updated?

CVE-2021-29482 was published on April 28, 2021 and was last updated on October 20, 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-2021-29482 — xz

HIGHFix: ulikunitz/xz@69c6093

CVE-2021-29482 is a high-severity (CVSS 7.5) CWE-835 vulnerability in github.com/ulikunitz/xz. A fix is available for github.com/ulikunitz/xz — see the affected versions and patch details below.

github.com/ulikunitz/xz fixes readUvarint Denial of Service (DoS)

Also known asGHSA-25xm-hr59-7c27GO-2020-0016

Published

Apr 28, 2021

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 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

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐹github.com/ulikunitz/xz

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

xz is a compression and decompression library focusing on the xz format completely written in Go. The function readUvarint used to read the xz container format may not terminate a loop provide malicous input.

Patches

The problem has been fixed in release v0.5.8.

Workarounds

Limit the size of the compressed file input to a reasonable size for your use case.

References

The standard library had recently the same issue and got the CVE-2020-16845 allocated.

For more information

If you have any questions or comments about this advisory:

Open an issue in xz.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/ulikunitz/xz`	all versions	0.5.8`go get github.com/ulikunitz/xz@v0.5.8`

Affected Products

1 product · 1 configurations

Application

xzxz_project

< 0.5.8

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/ulikunitz/xz, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/ulikunitz/xz to 0.5.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29482 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.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

In OpenShift Container Platform (OCP), OpenShift ServiceMesh (OSSM) and Red Hat Advanced Cluster Management for Kubernetes (RHACM) the affected components are behind OpenShift OAuth authentication, therefore the impact is low. In OCP before 4.7 the buildah, skopeo and podman packages include vulnerable version of…

Product	Fixed in	Advisory
OADP-1.0-RHEL-8	`oadp/oadp-velero-plugin-rhel8:1.0.1-5`	RHSA-2022:0687
OpenShift Service Mesh 2.0	`servicemesh-0:2.0.9-3.el8`	RHSA-2022:1276
Red Hat OpenStack Platform 16.2	`rhosp-rhel8-tech-preview/osp-director-operator:1.2.3-2`	RHSA-2022:2183
RHEL-8-CNV-4.8	`container-native-virtualization/vm-import-operator-rhel8:v4.8.0-18`	RHSA-2021:2920

Frequently Asked Questions

### Impact xz is a compression and decompression library focusing on the xz format completely written in Go. The function readUvarint used to read the xz container format may not terminate a loop provide malicous input. ### Patches The problem has been fixed in release v0.5.8. ### Workarounds Limit the size of the compressed file input to a reasonable size for your use case. ### References The standard library had recently the same issue and got the [CVE-2020-16845](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-16845) allocated. ### For more information If you have any questi