CVE-2024-3094: Malicious code was discovered in the upstream tarballs of xz, starting with version 5.6.0

This week

CRITICAL 10.0REMOTEDOWNGRADE

CVE-2024-3094 is a critical-severity flaw (CVSS 10.0) affecting xz. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Malicious code was discovered in the upstream tarballs of xz, starting with version 5.6.0. Through a series of complex obfuscations, the liblzma build process extracts a prebuilt object file from a disguised test file existing in the source code, which is then used to modify specific functions in the liblzma code. This results in a modified liblzma library that can be used by any software linked against this library, intercepting and modifying

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	10.0 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	90.9% (top 1%)
CISA exploited list	No
Weakness	CWE-506
Published	2024-03-29
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: tukaani

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2024-03-29 17:15 UTCPublished CVE record published
2026-06-17 07:43 UTCUpdated Record last modified

tukaani xz DOWNGRADE

Affected: 5.6.0 · 5.6.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.6.0

1. Check installed version

apt-cache policy xz || rpm -q xz || xz --version

2. No fixed release: DOWNGRADE to a release before 5.6.0 (Debian / Ubuntu)

apt-cache madison xz sudo apt install xz=<VERSION_BEFORE_5.6.0> sudo apt-mark hold xz

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list xz sudo dnf downgrade xz-<VERSION_BEFORE_5.6.0> sudo dnf versionlock add xz

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · sbcl · FIXED · 2.6.10-1.fc46 · FEDORA-2026-feab1a81c6 · source

sudo dnf upgrade --advisory=FEDORA-2026-feab1a81c6

Fedora ELN · python-archspec · FIXED · 0.2.7-1.eln159 · FEDORA-2026-e2a8272db6 · source

sudo dnf upgrade --advisory=FEDORA-2026-e2a8272db6

Ubuntu 20.04 · xz-utils · NOT AFFECTED

Ubuntu 22.04 · xz-utils · NOT AFFECTED

Ubuntu 24.04 · xz-utils · NOT AFFECTED

Debian 12 · xz-utils · NOT AFFECTED

Debian 13 · xz-utils · FIXED · 5.6.1+really5.4.5-1

sudo apt update && sudo apt install --only-upgrade xz-utils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' xz-utils)" ge "5.6.1+really5.4.5-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · xz · NOT AFFECTED

RHEL 6 · xz · NOT AFFECTED

RHEL 7 · xz · NOT AFFECTED

RHEL 8 · xz · NOT AFFECTED

RHEL 9 · xz · NOT AFFECTED

Alpine 3.20 · xz · FIXED · xz-5.6.1-r2

apk add --upgrade xz apk info -v xz

Alpine 3.21 · xz · FIXED · xz-5.6.1-r2

apk add --upgrade xz apk info -v xz

Alpine 3.22 · xz · FIXED · xz-5.6.1-r2

apk add --upgrade xz apk info -v xz

Alpine 3.23 · xz · FIXED · xz-5.6.1-r2

apk add --upgrade xz apk info -v xz

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: amlweems/xzbot (3553 stars)
GitHub PoC: lockness-Ko/xz-vulnerable-honeypot (147 stars)
GitHub PoC: FabioBaroni/CVE-2024-3094-checker (72 stars)
Write-up: lwn.net/Articles/967180/
Write-up: news.ycombinator.com/item?id=39877267
Write-up: news.ycombinator.com/item?id=39895344
GitHub PoC: 0xlane/xz-cve-2024-3094
GitHub PoC: 24Owais/threat-intel-cve-2024-3094

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2024-3094?

xz: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2024-3094 being exploited?

CVE-2024-3094 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2024-3094 affect?

CVE-2024-3094 affects xz. Severity is critical (CVSS 10.0). Malicious code was discovered in the upstream tarballs of xz, starting with version 5.6.0. Through a series of complex obfuscations, the liblzma build process extracts a prebuilt object file from a disguised test file existing in the sour

How urgent is CVE-2024-3094?

Priority 73/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Related CVEs

CVE-2022-1271 HIGH 8.8 UPGRADE DOWNGRADE An arbitrary file write vulnerability was found in GNU gzip's zgrep utility
CVE-2026-34743 MEDIUM 5.3 UPGRADE XZ Utils provide a general-purpose data-compression library plus command-line tools
CVE-2021-29482 HIGH 7.5 UPGRADE xz is a compression and decompression library focusing on the xz format completely written in Go
CVE-2020-22916 MEDIUM 5.5 DOWNGRADE An issue discovered in XZ 5.2.5 allows attackers to cause a denial of service via decompression of a crafted f
CVE-2015-4035 HIGH 7.8 UPGRADE scripts/xzgrep.in in xzgrep 5.2.x before 5.2.0, before 5.0.0 does not properly process file names containing s

References

← Back to latest CVEs