{"id":"CVE-2026-34743","title":"XZ Utils provide a general-purpose data-compression library plus command-line tools","summary":"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 wher…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwe":["CWE-122","CWE-131"],"vendor":"tukaani","product":"xz","affected":["xz < 5.8.3"],"patched":["xz 5.8.3"],"published":"2026-04-02","updated":"2026-07-21","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-34743","references":[{"url":"https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87","label":"security-advisories@github.com"},{"url":"https://github.com/tukaani-project/xz/releases/tag/v5.8.3","label":"security-advisories@github.com"},{"url":"https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv","label":"security-advisories@github.com"},{"url":"http://www.openwall.com/lists/oss-security/2026/03/31/13","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2026/07/msg00034.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34743.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-34743"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2454589"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-34743"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34743"},{"url":"https://access.redhat.com/errata/RHSA-2026:64787"},{"url":"https://access.redhat.com/errata/RHSA-2026:7647"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.0045,"epssPercentile":0.38452,"ingestedAt":"2026-07-21T23:55:35.214Z","slug":"CVE-2026-34743","body":"## Overview\n\nXZ 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.\n\n## Affected\n\n- `xz < 5.8.3`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `xz 5.8.3`\n\n## Vendor advisories\n\n- **RHSA-2026:64787** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:64787)\n- **RHSA-2026:7647** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:7647)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4, … · updated 2026-09-11 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34743.json)","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}