CVE-2024-3094
XZ Utils backdoor
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.
- CVSS
- 10.0Criticalscored by the publisher (CNA)
- Exploited in the wild
- Not knownUnvetted proof-of-concept code on GitHub; not in CISA KEV
- EPSS
- 90.9%chance of exploitation in the next 30 daystop 0.2% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 29 Mar 2024analysed here 12 Nov 2026
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
Products named in our analysis
- tukaani:xz
Fix and mitigation
WAF and other mitigations
Can a WAF block it? No. Malicious code was shipped inside the software itself. It runs from within, so a WAF never sees it.
Also consider: SBOM · artifact signing
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Not listed as of our last sync.
- Public exploit code
- Unvetted proof-of-concept code on GitHub: 88 GitHub proofs of concept
- CISA SSVC
- exploitation none, automatable yes, technical impact totalAssessed by CISA 2 Apr 2024 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
GitHub proofs of concept
- amlweems/xzbot3,553 stars
- lockness-Ko/xz-vulnerable-honeypot147 stars
- FabioBaroni/CVE-2024-3094-checker72 stars
- robertdfrench/ifuncd-up60 stars
and 84 more repositories
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 29 Mar 2024First proof-of-concept repository on GitHub (unvetted)
- 29 Mar 2024Published1 day later
- 2 Apr 2024CISA SSVC assessment: exploitation none3 days later
- 4 Nov 2026CVE record last updated947 days (about 3 years) later
- 12 Nov 2026Analysed by vulneraibility.com8 days later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | ChangedImpact crosses a security boundary into other components. | Impact crosses a security boundary into other components. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2024-3094 being exploited?
Not confirmed. CVE-2024-3094 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 91% probability of exploitation in the next 30 days.
How severe is CVE-2024-3094?
CVE-2024-3094 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2024-3094?
Yes. A fix has been recorded for CVE-2024-3094. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2024-3094 affect?
CVE-2024-3094 affects tukaani:xz. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
50 references in the CVE record, grouped by the tags the record gives them.
Other links (50)
- access.redhat.com /security/cve/CVE-2024-3094
- bugzilla.redhat.com /show_bug.cgi?id=2272210
- openwall.com /lists/oss-security/2024/03/29/4
- redhat.com /en/blog/urgent-security-alert-fedora-41-and-rawhide-users
- binarly.io /blog/persistent-risk-xz-utils-backdoor-still-lurking-in-docker-images
- ariadne.space /2024/04/02/the-xz-utils-backdoor-is-a-symptom-of-a-larger-problem/
Show 44 more
- arstechnica.com /security/2024/03/backdoor-found-in-widely-used-linux-utility-breaks-encrypted-s
- aws.amazon.com /security/security-bulletins/AWS-2024-002/
- blog.netbsd.org /tnf/entry/statement_on_backdoor_in_xz
- boehs.org /node/everything-i-know-about-the-xz-backdoor
- bugs.debian.org /cgi-bin/bugreport.cgi?bug=1068024
- bugs.gentoo.org /928134
- bugzilla.suse.com /show_bug.cgi?id=1222124
- discourse.nixos.org /t/cve-2024-3094-malicious-code-in-xz-5-6-0-and-5-6-1-tarballs/42405
- gist.github.com /thesamesam/223949d5a074ebc3dce9ee78baad9e27
- github.com /advisories/GHSA-rxwq-x6h5-x525
- github.com /amlweems/xzbot
- github.com /karcherm/xz-malware
- gynvael.coldwind.pl /?lang=en&id=782
- lists.debian.org /debian-security-announce/2024/msg00057.html
- lists.freebsd.org /archives/freebsd-security/2024-March/000248.html
- lwn.net /Articles/967180/
- news.ycombinator.com /item?id=39865810
- news.ycombinator.com /item?id=39877267
- news.ycombinator.com /item?id=39895344
- openssf.org /blog/2024/03/30/xz-backdoor-cve-2024-3094/
- research.swtch.com /xz-script
- research.swtch.com /xz-timeline
- security-tracker.debian.org /tracker/CVE-2024-3094
- security.alpinelinux.org /vuln/CVE-2024-3094
- security.archlinux.org /CVE-2024-3094
- security.netapp.com /advisory/ntap-20240402-0001/
- tukaani.org /xz-backdoor/
- twitter.com /LetsDefendIO/status/1774804387417751958
- twitter.com /debian/status/1774219194638409898
- twitter.com /infosecb/status/1774595540233167206
- twitter.com /infosecb/status/1774597228864139400
- ubuntu.com /security/CVE-2024-3094
- cisa.gov /news-events/alerts/2024/03/29/reported-supply-chain-compromise-affecting-xz-uti
- darkreading.com /vulnerabilities-threats/are-you-affected-by-the-backdoor-in-xz-utils
- kali.org /blog/about-the-xz-backdoor/
- tenable.com /blog/frequently-asked-questions-cve-2024-3094-supply-chain-backdoor-in-xz-utils
- theregister.com /2024/03/29/malicious_backdoor_xz/
- vicarius.io /vsociety/vulnerabilities/cve-2024-3094
- xeiaso.net /notes/2024/xz-vuln/
- openwall.com /lists/oss-security/2024/03/30/12
- openwall.com /lists/oss-security/2024/03/30/27
- openwall.com /lists/oss-security/2024/03/29/12
- openwall.com /lists/oss-security/2024/03/29/10
- openwall.com /lists/oss-security/2024/03/30/36
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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