Bug 2454589 (CVE-2026-34743)

Summary: CVE-2026-34743 xz: XZ Utils: Denial of Service via buffer overflow in index decoding
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in XZ Utils. When the `lzma_index_decoder()` function processes an empty index, and a subsequent `lzma_index_append()` operation is performed, insufficient memory is allocated. This can lead to a buffer overflow, potentially causing a denial of service (DoS) for affected systems.
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Description OSIDB Bzimport 2026-04-02 19:03:20 UTC 
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.