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An e2guardian security update has been released for Debian GNU/Linux 10 LTS to address a potential Man In the Middle (MITM) vulnerability.

[SECURITY] [DLA 3564-1] e2guardian security update

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Debian LTS Advisory DLA-3564-1 Chris Lamb
September 12, 2023
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Package : e2guardian
Version : 5.3.1-1+deb10u1
CVE ID : CVE-2021-44273
Debian Bug : 1003125

It was discovered that there was a potential Man In the Middle (MITM)
vulnerability in e2guardian, a web content filtering engine.

Validation of SSL certificates was missing in e2guardian's own MITM
prevention engine. In standalone mode (ie. acting as a proxy or a
transparent proxy) with SSL MITM enabled, e2guardian did not validate
hostnames in certificates of the web servers that it connected to,
and thus was itself vulnerable to MITM attacks.

For Debian 10 buster, this problem has been fixed in version

We recommend that you upgrade your e2guardian packages.

For the detailed security status of e2guardian please refer to
its security tracker page at:

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