# What is CVE-2024-3094?

> CVE-2024-3094 is a critical-severity flaw (CVSS 10.0) in Xz from Tukaani, published on 29 March 2024. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 91%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2024-3094

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 84 out of 100 (High); action: Patch now. Kept up to date as the evidence changes.
- **Severity:** Critical (CVSS 10.0 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 91% (latest exploit-likelihood forecast)
- **Published:** 29 March 2024
- **Record last updated:** 17 June 2026
- **Main product:** Xz from Tukaani
- **Affected products:** 1

## What is CVE-2024-3094? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### The official description

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.

### What kind of flaw is it?

- CWE-506: Embedded Malicious Code

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read data, change data and take it offline

Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Is CVE-2024-3094 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 91%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 86%, 86%, 90%, 90%, 90%, 91%, 91%.

### Timeline

- 29 March 2024: Published
- 17 June 2026: Record last updated

### How Precursor Intelligence ranks it

CVE-2024-3094 scores **84 out of 100 (High)**, with the action "Patch now".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2024-3094?

The published record lists 1 product.

- [Xz](https://www.precursorintelligence.com/product/tukaani/xz) by [Tukaani](https://www.precursorintelligence.com/vendors/tukaani) (Application): 5.6.0, 5.6.1

## How do I fix CVE-2024-3094?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2024-3094) (Vendor advisory)
- [bugzilla.redhat.com](https://bugzilla.redhat.com/show_bug.cgi?id=2272210) (Issue tracking, Vendor advisory)
- [redhat.com](https://www.redhat.com/en/blog/urgent-security-alert-fedora-41-and-rawhide-users) (Vendor advisory)
- [bugs.debian.org](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1068024) (Mailing list, Vendor advisory)
- [tukaani.org](https://tukaani.org/xz-backdoor/) (Issue tracking, Vendor advisory)
- [openwall.com](https://www.openwall.com/lists/oss-security/2024/03/29/4) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/10)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/12)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/5)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/29/8)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/12)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/27)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/36)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/03/30/5)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/04/16/5)
- [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/) (Third-party advisory)
- [aws.amazon.com](https://aws.amazon.com/security/security-bulletins/AWS-2024-002/) (Third-party advisory)
- [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) (Third-party advisory)
- [bugs.gentoo.org](https://bugs.gentoo.org/928134) (Issue tracking, Third-party advisory)
- [bugzilla.suse.com](https://bugzilla.suse.com/show_bug.cgi?id=1222124) (Issue tracking, Third-party advisory)
- [discourse.nixos.org](https://discourse.nixos.org/t/cve-2024-3094-malicious-code-in-xz-5-6-0-and-5-6-1-tarballs/42405) (Third-party advisory)
- [gist.github.com](https://gist.github.com/thesamesam/223949d5a074ebc3dce9ee78baad9e27) (Third-party advisory)
- [github.com](https://github.com/advisories/GHSA-rxwq-x6h5-x525) (Third-party advisory)
- [github.com](https://github.com/amlweems/xzbot)
- [github.com](https://github.com/karcherm/xz-malware) (Third-party advisory)
- [gynvael.coldwind.pl](https://gynvael.coldwind.pl/?lang=en&id=782) (Technical description, Third-party advisory)
- [lists.debian.org](https://lists.debian.org/debian-security-announce/2024/msg00057.html) (Mailing list, Third-party advisory)
- [lists.freebsd.org](https://lists.freebsd.org/archives/freebsd-security/2024-March/000248.html) (Third-party advisory)
- [lwn.net](https://lwn.net/Articles/967180/) (Issue tracking, Third-party advisory)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=39865810) (Issue tracking, Third-party advisory)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=39877267) (Issue tracking)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=39895344)
- [openssf.org](https://openssf.org/blog/2024/03/30/xz-backdoor-cve-2024-3094/) (Third-party advisory)
- [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) (Third-party advisory)
- [security.alpinelinux.org](https://security.alpinelinux.org/vuln/CVE-2024-3094) (Third-party advisory)
- [security.archlinux.org](https://security.archlinux.org/CVE-2024-3094) (Third-party advisory)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20240402-0001/)
- [twitter.com](https://twitter.com/LetsDefendIO/status/1774804387417751958) (Third-party advisory)
- [twitter.com](https://twitter.com/debian/status/1774219194638409898) (Press/media coverage)
- [twitter.com](https://twitter.com/infosecb/status/1774595540233167206) (Press/media coverage)
- [twitter.com](https://twitter.com/infosecb/status/1774597228864139400) (Press/media coverage)
- [ubuntu.com](https://ubuntu.com/security/CVE-2024-3094) (Third-party advisory)
- [binarly.io](https://www.binarly.io/blog/persistent-risk-xz-utils-backdoor-still-lurking-in-docker-images)

## Questions

### What is CVE-2024-3094?

CVE-2024-3094 is a critical-severity flaw in Xz from Tukaani, published on 29 March 2024. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### How serious is CVE-2024-3094?

It scores 10.0 out of 10 on the CVSS severity scale, which is critical. Our risk score for CVE-2024-3094 is 84 out of 100, which is High. Its action is "Patch now". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2024-3094 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 91%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2024-3094 affect?

For Xz from Tukaani: 5.6.0, 5.6.1.

### How do I fix CVE-2024-3094?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2024-3094 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
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