CVE Tools
Sign in

CVE-2026-34743

XZ Utils: Buffer overflow in lzma_index_append()

Published: Apr 2, 2026Updated: Jul 24, 2026 Sources: CVE List NVD BDUCWE-122
5.3MEDIUM
NVD MITRE
EPSS Score
0.4%
Top 63.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
Open in CVSS calculator →

Weaknesses

CWE-122

Affected Products

tukaani
oss-projectaka tukaani xz
xzLibrary
OSS Libraries / generic-library
tukaani-project
oss-project·FIaka tukaani, tukaani project
xzLibrary
OSS Libraries / generic-library
ООО «Ред Софт»
commercial·RUaka red soft
РЕД ОСOn-premOS
Operating Systems / linux-distro
Сообщество свободного программного обеспечения
oss-projectaka fsf
XZ UtilsLibraryLibrary
OSS Libraries / generic-library

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-34743?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Privilege Escalation
View detailed technique mapping

References

https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87
github.com
https://github.com/tukaani-project/xz/releases/tag/v5.8.3
github.com
https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv
github.com
and 4 more references View all →

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-34743 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows