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Debian LTS Advisory DLA-3540-1                debian-lts@lists.debian.org
https://www.debian.org/lts/security/                      Markus Koschany
August 23, 2023                               https://wiki.debian.org/LTS
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Package        : mediawiki
Version        : 1:1.31.16-1+deb10u6
CVE ID         : CVE-2023-29141

An auto-block can occur for an untrusted X-Forwarded-For header in
MediaWiki, a website engine for collaborative work.

X-Forwarded-For is not necessarily trustworthy and can specify multiple IP
addresses in a single header, all of which are checked for blocks. When a user
is autoblocked, the wiki will create an IP block behind-the-scenes for that
user without exposing the user's IP on-wiki. However, spoofing XFF would let an
attacker guess at the IPs of users who have active autoblocks, since the
block message includes the username of the original block target.

For Debian 10 buster, this problem has been fixed in version
1:1.31.16-1+deb10u6.

We recommend that you upgrade your mediawiki packages.

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

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