CVE-2026-34743: CWE-122: Heap-based Buffer Overflow in tukaani-project xz
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.
AI Analysis
Technical Summary
The tukaani-project xz utility, which provides data compression functionality, contains a heap-based buffer overflow vulnerability (CWE-122) in versions before 5.8.3. When lzma_index_decoder() decodes an Index containing zero Records, the internal lzma_index structure is improperly initialized, causing lzma_index_append() to allocate too little memory. This results in a heap buffer overflow. The vulnerability is addressed by a patch in version 5.8.3.
Potential Impact
The vulnerability allows a heap-based buffer overflow which could potentially lead to memory corruption. However, the CVSS score is low (1.7), indicating limited impact and complexity. There are no known exploits in the wild. The vulnerability requires network attack vector with low complexity and partial attack complexity, but no privileges or user interaction are needed.
Mitigation Recommendations
Upgrade to tukaani-project xz version 5.8.3 or later, where this vulnerability is patched. No other mitigation is indicated or required according to the available data.
CVE-2026-34743: CWE-122: Heap-based Buffer Overflow in tukaani-project xz
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 v4.0
Score 1.7low
Affected software
pkg:github/tukaani-project/xzRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The tukaani-project xz utility, which provides data compression functionality, contains a heap-based buffer overflow vulnerability (CWE-122) in versions before 5.8.3. When lzma_index_decoder() decodes an Index containing zero Records, the internal lzma_index structure is improperly initialized, causing lzma_index_append() to allocate too little memory. This results in a heap buffer overflow. The vulnerability is addressed by a patch in version 5.8.3.
Potential Impact
The vulnerability allows a heap-based buffer overflow which could potentially lead to memory corruption. However, the CVSS score is low (1.7), indicating limited impact and complexity. There are no known exploits in the wild. The vulnerability requires network attack vector with low complexity and partial attack complexity, but no privileges or user interaction are needed.
Mitigation Recommendations
Upgrade to tukaani-project xz version 5.8.3 or later, where this vulnerability is patched. No other mitigation is indicated or required according to the available data.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-03-30T19:17:10.224Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 69cec35ae6bfc5ba1dfb4cd9
Added to database: 04/02/2026, 19:28:26 UTC
Last enriched: 07/22/2026, 21:58:31 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 105
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