CVE-2026-34743
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…
Does this matter?
Lower severity and a low EPSS score (0.45%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 1.7 LOWCVSS: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/M
- EPSS
- 0.45% probability · 38th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-122
- Affected
- tukaani/xz
- Source
- security-advisories@github.com
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
- https://lists.debian.org/debian-lts-announce/2026/07/msg00034.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.