CVE-2026-22184

Publication date 7 January 2026

Last updated 21 January 2026


Ubuntu priority

Description

zlib versions up to and including 1.3.1.2 include a global buffer overflow in the untgz utility located under contrib/untgz. The vulnerability is limited to the standalone demonstration utility and does not affect the core zlib compression library. The flaw occurs when a user executes the untgz command with an excessively long archive name supplied via the command line, leading to an out-of-bounds write in a fixed-size global buffer.

Read the notes from the security team

Status

Package Ubuntu Release Status
zlib 25.10 questing
Not affected
25.04 plucky
Not affected
24.04 LTS noble
Not affected
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
rsync 25.10 questing
Not affected
25.04 plucky
Not affected
24.04 LTS noble
Not affected
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
zsync 25.10 questing
Needs evaluation
25.04 plucky Ignored end of life, was needs-triage
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
klibc 25.10 questing
Not affected
25.04 plucky
Not affected
24.04 LTS noble
Not affected
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected

Notes


mdeslaur

since 3.2.0-1, rsync builds with the system zlib


0xnishit

untgz not presnet since 1:1.2.3.5.dfsg-1 version in zlib


Bruce

Disputed by upstream as affected file "untag.c" under the contrib directory is not part of zlibc. (See https://github.com/madler/zlib/issues/754)