CVE-2026-34743

Name: CVE-2026-34743
Creator: NVD / NIST
Published: 2026-04-02T19:21:33.187+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 1.7/10EPSS 0.35%

Last modified Jun 17, 2026

CVE-2026-34743 is a low-severity vulnerability rated 1.7/10 on the CVSS scale. XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. EPSS estimates a 0.35% chance of exploitation in the next 30 days.

Description

XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. This issue has been patched in version 5.8.3.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS 4.0

1.7/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.35%

27.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-122

Affected Software

Vendor	Product	Versions
Tukaani	Xz	< 5.8.3

References

https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87Patch
https://github.com/tukaani-project/xz/releases/tag/v5.8.3Product, Release Notes
https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhvVendor Advisory
http://www.openwall.com/lists/oss-security/2026/03/31/13Mailing List, Patch, Third Party Advisory

Timeline

Published: Apr 2, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34743?

How severe is CVE-2026-34743?

CVE-2026-34743 has a CVSS score of 1.7/10 (LOW severity). The EPSS model estimates a 0.35% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34743?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34743?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST