CVE-2026-34743
XZ Utils: Buffer overflow in lzma_index_append()
02 Description
XZ Utils: Buffer overflow in lzma_index_append()
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.51% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 43.5% of scored records. A rank, not a probability.
- NVD base score
- 1.7 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- 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
- NVD analysis status
- Modified. NVD last modified this record on 2026-07-24.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-04-02 18:36Z6 MO AGO
- Last updated
- 2026-07-21 22:19Z3 MO AGO
- Reserved
- 2026-03-30
- Assigning CNA
- GitHub_M
- Record state
- PUBLISHED
- Severity
- Low (CVSS 1.7)
- CNA CVSS vector
- 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
- Weaknesses
- Data version
- 5.2
- Document digest
- 78942c62a1e58485e25fa7335c5b7a8fa1bcaa6699a3eaa1145ceefe2ef5eee3
05 Affected products
06 References
- github.comhttps://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv
- github.comhttps://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87
- github.comhttps://github.com/tukaani-project/xz/releases/tag/v5.8.3
- www.openwall.comhttp://www.openwall.com/lists/oss-security/2026/03/31/13
- lists.debian.orghttps://lists.debian.org/debian-lts-announce/2026/07/msg00034.html
07 Fixed in
AlmaLinux 9
- xz Fixed in 5.2.5-8.el9_8.1
- xz-devel Fixed in 5.2.5-8.el9_8.1
- xz-libs Fixed in 5.2.5-8.el9_8.1
- xz-lzma-compat Fixed in 5.2.5-8.el9_8.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 10
- xz Fixed in 1:5.6.2-4.el10_2.1
- xz-devel Fixed in 1:5.6.2-4.el10_2.1
- xz-libs Fixed in 1:5.6.2-4.el10_2.1
- xz-lzma-compat Fixed in 1:5.6.2-4.el10_2.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 9
- xz Fixed in 5.2.5-8.el9_8.1
- xz-devel Fixed in 5.2.5-8.el9_8.1
- xz-libs Fixed in 5.2.5-8.el9_8.1
- xz-lzma-compat Fixed in 5.2.5-8.el9_8.1
Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 10
- xz Fixed in 1:5.6.2-4.el10_2.1
- xz-devel Fixed in 1:5.6.2-4.el10_2.1
- xz-libs Fixed in 1:5.6.2-4.el10_2.1
- xz-lzma-compat Fixed in 1:5.6.2-4.el10_2.1
Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- xz-utils Fixed in 5.4.1-1+deb12u1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- xz-utils Fixed in 5.8.1-1+deb13u1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- xz-utils Fixed in 5.8.3-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- xz-utils Fixed in 5.2.5-2ubuntu1.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- xz-utils Fixed in 5.6.1+really5.4.5-1ubuntu0.3
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 25.10
- xz-utils Fixed in 5.8.1-1ubuntu0.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- xz-utils Fixed in 5.1.1alpha+20120614-2ubuntu2.14.04.1+esm2Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- xz-utils Fixed in 5.1.1alpha+20120614-2ubuntu2.16.04.1+esm2Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 18.04 LTS
- xz-utils Fixed in 5.2.2-1.3ubuntu0.1+esm1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 20.04 LTS
- xz-utils Fixed in 5.2.4-1ubuntu1.1+esm1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.