# CVE-2026-34743

## Summary

- **CVE ID:** CVE-2026-34743
- **Severity:** LOW
- **CVSS Score:** 1.7 (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)
- **CWE:** CWE-122
- **Published:** Apr 2, 2026
- **Last Modified:** Sep 14, 2026

## 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.

## Affected Products

- tukaani-project — xz (< 5.8.3)

## References

- [CNA](https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv)
- [CNA](https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87)
- [CNA](https://github.com/tukaani-project/xz/releases/tag/v5.8.3)
- [CVE](http://www.openwall.com/lists/oss-security/2026/03/31/13)
- [CVE](https://lists.debian.org/debian-lts-announce/2026/07/msg00034.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.45%
- **EPSS Percentile:** 38.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._