---
title: "CVE-2024-3094: Xz: malicious code in distributed source"
url: https://erroneo.us/security/cve/CVE-2024-3094/
description: "CVE-2024-3094 (xz): Malicious code was discovered in the upstream tarballs of xz, starting with version 5.6.0. Through a series of complex obfuscations, the…"
type: vulnerability-record
section: "Security Digest"
date_published: 2024-03-29
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2024-3094"
kev: false
cvss: 10
epss: 0.909
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2024-3094: Xz: malicious code in distributed source

**Signal:** High exploit likelihood. EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 90.9% , percentile 99.8: FIRST’s model estimates a 90.9% chance of exploitation activity in the next 30 days, higher than 99.8% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. xz-utils Backdoor in liblzma 5.6.0/5.6.1 (CVE-2024-3094) — The backdoor only reached rolling and pre-release distributions for a few weeks before discovery; stable enterprise releases never shipped it, but any machine that ran xz 5.6.0 or 5.6.1 should be checked.

## What it is

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 the data interaction with this library.

## Affected products (CVE record)

-  xz: 5.6.0, 5.6.1
- Red Hat Red Hat Enterprise Linux 10: see advisory
- Red Hat Red Hat Enterprise Linux 6: see advisory
- Red Hat Red Hat Enterprise Linux 7: see advisory
- Red Hat Red Hat Enterprise Linux 8: see advisory
- Red Hat Red Hat Enterprise Linux 9: see advisory
- Red Hat Red Hat JBoss Enterprise Application Platform 8: see advisory

## Severity

- redhat CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 90.90% probability of exploitation activity in the next 30 days; percentile 99.8.

## Sources

- [CVE.org record CVE-2024-3094](https://www.cve.org/CVERecord?id=CVE-2024-3094)
- [NVD entry CVE-2024-3094](https://nvd.nist.gov/vuln/detail/CVE-2024-3094)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2024-3094)
- [RHBZ#2272210](https://bugzilla.redhat.com/show_bug.cgi?id=2272210)
- [openwall.com](https://www.openwall.com/lists/oss-security/2024/03/29/4)
- [redhat.com](https://www.redhat.com/en/blog/urgent-security-alert-fedora-41-and-rawhide-users)
- [binarly.io](https://www.binarly.io/blog/persistent-risk-xz-utils-backdoor-still-lurking-in-docker-images)
- [ariadne.space](https://ariadne.space/2024/04/02/the-xz-utils-backdoor-is-a-symptom-of-a-larger-problem/)
- [arstechnica.com](https://arstechnica.com/security/2024/03/backdoor-found-in-widely-used-linux-utility-breaks-encrypted-ssh-connections/)
- [aws.amazon.com](https://aws.amazon.com/security/security-bulletins/AWS-2024-002/)
- [blog.netbsd.org](https://blog.netbsd.org/tnf/entry/statement_on_backdoor_in_xz)
- [boehs.org](https://boehs.org/node/everything-i-know-about-the-xz-backdoor)
- [bugs.debian.org](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1068024)
- [bugs.gentoo.org](https://bugs.gentoo.org/928134)
- [bugzilla.suse.com](https://bugzilla.suse.com/show_bug.cgi?id=1222124)
- [discourse.nixos.org](https://discourse.nixos.org/t/cve-2024-3094-malicious-code-in-xz-5-6-0-and-5-6-1-tarballs/42405)
- [gist.github.com](https://gist.github.com/thesamesam/223949d5a074ebc3dce9ee78baad9e27)
- [github.com](https://github.com/advisories/GHSA-rxwq-x6h5-x525)
- [github.com](https://github.com/amlweems/xzbot)
- [github.com](https://github.com/karcherm/xz-malware)
- [gynvael.coldwind.pl](https://gynvael.coldwind.pl/?lang=en&id=782)
- [lists.debian.org](https://lists.debian.org/debian-security-announce/2024/msg00057.html)
- [lists.freebsd.org](https://lists.freebsd.org/archives/freebsd-security/2024-March/000248.html)
- [lwn.net](https://lwn.net/Articles/967180/)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=39865810)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=39877267)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=39895344)
- [openssf.org](https://openssf.org/blog/2024/03/30/xz-backdoor-cve-2024-3094/)
- [research.swtch.com](https://research.swtch.com/xz-script)
- [research.swtch.com](https://research.swtch.com/xz-timeline)
- [security-tracker.debian.org](https://security-tracker.debian.org/tracker/CVE-2024-3094)
- [security.alpinelinux.org](https://security.alpinelinux.org/vuln/CVE-2024-3094)
- [security.archlinux.org](https://security.archlinux.org/CVE-2024-3094)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20240402-0001/)
- [tukaani.org](https://tukaani.org/xz-backdoor/)
- [twitter.com](https://twitter.com/LetsDefendIO/status/1774804387417751958)
- [twitter.com](https://twitter.com/debian/status/1774219194638409898)
- [twitter.com](https://twitter.com/infosecb/status/1774595540233167206)
- [twitter.com](https://twitter.com/infosecb/status/1774597228864139400)
- [ubuntu.com](https://ubuntu.com/security/CVE-2024-3094)
- [cisa.gov](https://www.cisa.gov/news-events/alerts/2024/03/29/reported-supply-chain-compromise-affecting-xz-utils-data-compression-library-cve-2024-3094)
- [darkreading.com](https://www.darkreading.com/vulnerabilities-threats/are-you-affected-by-the-backdoor-in-xz-utils)
- [kali.org](https://www.kali.org/blog/about-the-xz-backdoor/)
- [tenable.com](https://www.tenable.com/blog/frequently-asked-questions-cve-2024-3094-supply-chain-backdoor-in-xz-utils)
- [theregister.com](https://www.theregister.com/2024/03/29/malicious_backdoor_xz/)
- [vicarius.io](https://www.vicarius.io/vsociety/vulnerabilities/cve-2024-3094)
- [xeiaso.net](https://xeiaso.net/notes/2024/xz-vuln/)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/12)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/27)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/12)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/10)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/36)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/04/16/5)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/8)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/5)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/5)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/4)

---
Source page: https://erroneo.us/security/cve/CVE-2024-3094/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt