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Debian LTS xz-utils Critical Buffer Overflow Vuln DLA-4690-1 CVE-2026-34743

debian lts
Calendar Grey July 21, 2026
Scroller Debian Lts
An important security update for xz-utils addressing a critical buffer overflow issue. Upgrade is recommended for Debian LTS.
It was discovered that there was a potential buffer overflow in xz-utils, a popular data-compression utility and library
Topics%20covered

Topics Covered

security advisory buffer overflow critical xz-utils fixed deblts

Summary

CVE-2026-34743

If the lzma_index_decoder function 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 therefore occur.

For Debian 11 bullseye, this problem has been fixed in version
5.2.5-2.1~deb11u2;

We recommend that you upgrade your xz-utils packages.

For the detailed security status of xz-utils please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/xz-utils

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS



Severity
critical
Lowest
Low
Medium
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Critical

Package: xz-utils
Version: 5.2.5-2.1~deb11u2
CVE ID: CVE-2026-34743
Debian Bug: 1132497

Topics%20covered

Topics Covered

security advisory buffer overflow critical xz-utils fixed deblts

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