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CVE-2026-34743
XZ Utils: Buffer overflow in lzma_index_append()
Low1.7EPSS 0.53%
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | Low1.7 | 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 |
| NVDNVD · Modified | 4.0 | Low1.7 | 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/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 (exploitation in 30 days)
- 0.53% · top 55% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 1.7.
Weakness
Affected products
- affected < 5.8.3
References (5)
- https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv (opens in a new tab)x_refsource_CONFIRM
- https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87 (opens in a new tab)x_refsource_MISC
- https://github.com/tukaani-project/xz/releases/tag/v5.8.3 (opens in a new tab)x_refsource_MISC
- http://www.openwall.com/lists/oss-security/2026/03/31/13 (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2026/07/msg00034.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2026-34743)Record last updated .