Low 1.7Published Apr 2, 2026

CVE-2026-34743XZ Utils: Buffer overflow in lzma_index_append()

Updated under an hour ago (Oct 26, 2026, 11:30 PM ET)

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It affects tukaani-project xz and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for tukaani-project xz

Exploited in the last 30 days

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.

CVSS: 1.7 LOW (v4.0, CNA)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
Weakness (CWE): CWE-122
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Jul 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

tukaani-project xz tukaani_project:xz (from the name)	before 5.8.3	CNA record
tukaani xz tukaani:xz	before 5.8.3	NVD

References

References

https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv	x-refsource-confirm, vendor-advisory
https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87	x-refsource-misc, patch
https://github.com/tukaani-project/xz/releases/tag/v5.8.3	x-refsource-misc, product, release-notes
http://www.openwall.com/lists/oss-security/2026/03/31/13	mailing-list, patch, third-party-advisory
https://lists.debian.org/debian-lts-announce/2026/07/msg00034.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.