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

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.

Published: 2024-03-29 Last update: 2025-08-19 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-3094 is rated High Risk (76.1/100): CVSS Critical severity, with high exploitation likelihood (EPSS 85.97%, 100th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +1.17% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-3094

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 84.80% 85.97% +1.17%
2 2026-06-08 85.06% 84.80% -0.25%
3 2026-06-02 — 85.06% —

Full EPSS history (94 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-3094

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]
10.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]

Weakness enumeration for CVE-2024-3094

OS Trackers for CVE-2024-3094

vendor priority summary link
alpine — CVE-2024-3094: 2 source package rows (lighttpd, xz); 8 state rows across 6 repos (3.17-main, 3.18-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 8, open 0. https://security.alpinelinux.org/vuln/CVE-2024-3094
debian unimportant CVE-2024-3094 unimportant priority: Debian including 1 source packages (xz-utils), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2024-3094
gentoo high CVE-2024-3094: 1 GLSA(s) (202403-04), 1 atom(s) (app-arch/xz-utils); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-3094
redhat critical — https://access.redhat.com/security/cve/CVE-2024-3094
suse critical CVE-2024-3094 severity critical: SUSE including 18 source package names (liblzma5, liblzma5-32bit, …), 159 product×package rows across 37 product lines (SUSE Enterprise Storage 7.1, SUSE Linux Enterprise High Performance Computing 12 SP5, … (37 product lines)): Known Not Affected 147, Fixed 12. https://www.suse.com/security/cve/CVE-2024-3094/
ubuntu critical CVE-2024-3094 critical priority: Ubuntu including 1 source packages (xz-utils), 8 status rows across 8 suites (bionic, focal, jammy, mantic, noble, trusty, upstream, xenial): not-affected 7, needs-triage 1. https://ubuntu.com/security/CVE-2024-3094

Affected software / configurations for CVE-2024-3094

Vendor Product Version Raw CPE
tukaani xz 5.6.0 cpe:2.3:a:tukaani:xz:5.6.0:*:*:*:*:*:*:*
tukaani xz 5.6.1 cpe:2.3:a:tukaani:xz:5.6.1:*:*:*:*:*:*:*

References for CVE-2024-3094

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