CVE-2024-3094: Xz: malicious code in distributed source
Noroxi assessment
Priority: This week (action score 67/100)
- A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 90.9% (FIRST EPSS); higher than 99.8% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: lighttpd (Alpine:v3.15) 1.4.76-r0; xz (Alpine:v3.20) 5.6.1-r2; xz-utils (Debian:13) 5.6.1+really5.4.5-1.
Don’t wait for the next maintenance window. Upgrade to lighttpd (Alpine:v3.15) 1.4.76-r0; xz (Alpine:v3.20) 5.6.1-r2; xz-utils (Debian:13) 5.6.1+really5.4.5-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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
- Mar 29, 2024
- Updated
- Aug 4, 2026
- EPSS
- 90.9% · 99th percentile
- CWE
- CWE-506
Report tools
Action score
67
This week
Don’t wait for the next maintenance window.
- CVSS
- 40 / 40 · 10.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 27 / 30 · 90.9%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 10.0
- CNA · redhat
- 10.0
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| tukaani | xz | cpe:2.3:a:tukaani:xz |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- tukaani xz5.6.0
- tukaani xz5.6.1
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
github.com/tukaani-project/xz xz
- 5.6.0, 5.6.1affected
Red Hat Red Hat Enterprise Linux 10
- all versionsunknown
Red Hat Red Hat Enterprise Linux 6
- all versionsunknown
Red Hat Red Hat Enterprise Linux 7
- all versionsunknown
Red Hat Red Hat Enterprise Linux 8
- all versionsunknown
Red Hat Red Hat Enterprise Linux 9
- all versionsunknown
Red Hat Red Hat JBoss Enterprise Application Platform 8
- all versionsunknown
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.15 | lighttpd | before 1.4.76-r0 | 1.4.76-r0 |
| Alpine:v3.20 | xz | before 5.6.1-r2 | 5.6.1-r2 |
| Debian:13 | xz-utils | before 5.6.1+really5.4.5-1 | 5.6.1+really5.4.5-1 |
| openSUSE:Tumbleweed | xz | before 5.6.2-1.1 | 5.6.2-1.1 |
Same product
tukaani: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-4035scripts/xzgrep.in in xzgrep 5.2.x before 5.2.0, before 5.0.0 does not properly process file names containing semicolons, which allows remote31Monitor
- CVE-2020-22916An issue discovered in XZ 5.2.5 allows attackers to cause a denial of service via decompression of a crafted file.22Monitor
- CVE-2026-34743XZ Utils: Buffer overflow in lzma_index_append()6Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:lighttpd | 1.4.76-r0 · Alpine:v3.15 | Package registry (OSV) |
| alpine:xz | 5.6.1-r2 · Alpine:v3.20 | Package registry (OSV) |
| debian:xz-utils | 5.6.1+really5.4.5-1 · Debian:13 | Package registry (OSV) |
| opensuse:xz | 5.6.2-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Nuclei detection template ×1
- Proof-of-concept repository on GitHub ×50
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Nuclei detection template | Nuclei template CVE-2024-3094 | — |
| Proof-of-concept repository on GitHub | stars:54 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:72 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:4 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:9 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-03-29 |
| Proof-of-concept repository on GitHub | stars:4 | 2024-03-30 |
| Proof-of-concept repository on GitHub | stars:11 | 2024-03-30 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-03-30 |
| Proof-of-concept repository on GitHub | stars:1 | 2024-03-30 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-1 d
- Published
- TodayNov 4, 2026+950 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-506 · Embedded Malicious CodeCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
- Data Obfuscation: SteganographyT1001.002
- Obfuscated Files or Information: SteganographyT1027.003
- Obfuscated Files or Information: Compile After DeliveryT1027.004
- Obfuscated Files or Information: Embedded PayloadsT1027.009
- Supply Chain Compromise: Compromise Software Dependencies and Development ToolsT1195.001
- Supply Chain Compromise: Compromise Software Supply ChainT1195.002
- Signed Binary Proxy Execution: Compiled HTML FileT1218.001
- Template InjectionT1221
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- bugzilla.redhat.com/show_bug.cgi?id=2272210
- www.openwall.com/lists/oss-security/2024/03/29/4
- www.redhat.com/en/blog/urgent-security-alert-fedora-41-and-rawhide-users
- www.openwall.com/lists/oss-security/2024/03/29/10
- www.openwall.com/lists/oss-security/2024/03/29/12
- www.openwall.com/lists/oss-security/2024/03/29/4
- www.openwall.com/lists/oss-security/2024/03/29/5
- www.openwall.com/lists/oss-security/2024/03/29/8
- www.openwall.com/lists/oss-security/2024/03/30/12
- www.openwall.com/lists/oss-security/2024/03/30/27
- www.openwall.com/lists/oss-security/2024/03/30/36
- www.openwall.com/lists/oss-security/2024/03/30/5
- www.openwall.com/lists/oss-security/2024/04/16/5
- ariadne.space/2024/04/02/the-xz-utils-backdoor-is-a-symptom-of-a-larger-problem/
- arstechnica.com/security/2024/03/backdoor-found-in-widely-used-linux-utility-breaks-encrypted-ssh-connections/
- 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
Vendor advisories and official records. Exploit/PoC links are deliberately left out.