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 library versions before 5.8.3 contain a heap-based buffer overflow vulnerability (CWE-122) triggered when lzma_index_decoder() decodes an Index with zero Records. This leaves the internal lzma_index structure improperly initialized, causing lzma_index_append() to allocate too little memory and overflow the buffer. The vulnerability is fixed in version 5.8.3.
Potential Impact
Successful exploitation could lead to a heap-based buffer overflow, potentially causing application crashes or memory corruption. However, the low CVSS score and lack of known exploits suggest limited impact in practice.
Mitigation Recommendations
Upgrade to tukaani-project xz version 5.8.3 or later, where this vulnerability is patched. No other mitigation is indicated.
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The tukaani-project xz library versions before 5.8.3 contain a heap-based buffer overflow vulnerability (CWE-122) triggered when lzma_index_decoder() decodes an Index with zero Records. This leaves the internal lzma_index structure improperly initialized, causing lzma_index_append() to allocate too little memory and overflow the buffer. The vulnerability is fixed in version 5.8.3.
Potential Impact
Successful exploitation could lead to a heap-based buffer overflow, potentially causing application crashes or memory corruption. However, the low CVSS score and lack of known exploits suggest limited impact in practice.
Mitigation Recommendations
Upgrade to tukaani-project xz version 5.8.3 or later, where this vulnerability is patched. No other mitigation is indicated.
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: 4/2/2026, 7:28:26 PM
Last enriched: 4/9/2026, 10:48:54 PM
Last updated: 5/20/2026, 9:36:55 PM
Views: 47
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