FreeBSD Security Advisory FreeBSD-SA-22:08.zlib


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============================================================================= FreeBSD-SA-22:08.zlib Security Advisory The FreeBSD Project
Topic: zlib compression out-of-bounds write
Category: zlib Module: contrib Announced: 2022-04-06 Credits: Danilo Ramos of Eideticom Tavis Ormandy of Google Project Zero Affects: All supported versions of FreeBSD. Corrected: 2022-04-04 19:30:33 UTC (stable/13, 13.1-STABLE) 2022-04-04 20:02:42 UTC (releng/13.1, 13.1-RC1-p1) 2022-04-06 03:04:19 UTC (releng/13.0, 13.0-RELEASE-p11) 2022-04-04 01:07:59 UTC (stable/12, 12.3-STABLE) 2022-04-06 03:06:39 UTC (releng/12.3, 12.3-RELEASE-p5) CVE Name: CVE-2018-25032
For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit .
I. Background
zlib is a compression library used by numerous applications, as well as some FreeBSD kernel components, to provide data compression/decompression routines.
II. Problem Description
Certain inputs can cause zlib’s compression routine to overwrite an internal buffer with compressed data. This issue may require the use of uncommon or non-default compression parameters.
III. Impact
The out-of-bounds write may result in memory corruption and an application crash or kernel panic.
IV. Workaround
No workaround is available.
V. Solution
Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot.
Perform one of the following:
1) To update your vulnerable system via a binary patch:
Systems running a RELEASE version of FreeBSD on the amd64, i386, or (on FreeBSD 13 and later) arm64 platforms can be updated via the freebsd-update(8) utility:
# freebsd-update fetch # freebsd-update install # shutdown -r +10min “Rebooting for a security update”
2) To update your vulnerable system via a source code patch:
The following patches have been verified to apply to the applicable FreeBSD release branches.
a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility.
# fetch security.FreeBSD.org/patches/SA-22:08/zlib.patch # fetch security.FreeBSD.org/patches/SA-22:08/zlib.patch.asc # gpg –verify zlib.patch.asc
b) Apply the patch. Execute the following commands as root:
# cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in .
Recompile the operating system using buildworld and installworld as described in .
Reboot the system.
VI. Correction details
This issue is corrected by the corresponding Git commit hash or Subversion revision number in the following stable and release branches:
Branch/path Hash Revision – ————————————————————————- stable/13/ c4727a47f18c stable/13-n250251 releng/13.1/ f5196112e8bd releng/13.1-n250070 releng/13.0/ 9854ff088002 releng/13.0-n244799 stable/12/ r371856 releng/12.3/ r371875 – ————————————————————————-
For FreeBSD 13 and later:
Run the following command to see which files were modified by a particular commit:
# git show –stat
Or visit the following URL, replacing NNNNNN with the hash:

To determine the commit count in a working tree (for comparison against nNNNNNN in the table above), run:
# git rev-list –count –first-parent HEAD
For FreeBSD 12 and earlier:
Run the following command to see which files were modified by a particular revision, replacing NNNNNN with the revision number:
# svn diff -cNNNNNN –summarize svn://svn.freebsd.org/base
Or visit the following URL, replacing NNNNNN with the revision number:

VII. References


The latest revision of this advisory is available at —–BEGIN PGP SIGNATURE—–
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