Ubuntu Security Notice 6939-1 - Phillip Szelat discovered that Exim misparses multiline MIME header filenames. A remote attacker could use this issue to bypass a MIME filename extension-blocking protection mechanism and possibly deliver executable attachments to the mailboxes of end users.
582b87650e7c0b3fca6b658c3b550c8444aa2cb4f55af6f2d339070de3ef0ea8
==========================================================================
Ubuntu Security Notice USN-6939-1
July 31, 2024
exim4 vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
Summary:
Exim could be made to bypass a MIME filename extension-blocking
protection mechanism if it received specially crafted input.
Software Description:
- exim4: Exim is a mail transport agent
Details:
Phillip Szelat discovered that Exim misparses multiline MIME header
filenames. A remote attacker could use this issue to bypass a MIME filename
extension-blocking protection mechanism and possibly deliver executable
attachments to the mailboxes of end users.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 24.04 LTS
exim4 4.97-4ubuntu4.1
exim4-base 4.97-4ubuntu4.1
eximon4 4.97-4ubuntu4.1
Ubuntu 22.04 LTS
exim4 4.95-4ubuntu2.6
exim4-base 4.95-4ubuntu2.6
eximon4 4.95-4ubuntu2.6
Ubuntu 20.04 LTS
exim4 4.93-13ubuntu1.12
exim4-base 4.93-13ubuntu1.12
eximon4 4.93-13ubuntu1.12
Ubuntu 18.04 LTS
exim4 4.90.1-1ubuntu1.10+esm5
Available with Ubuntu Pro
exim4-base 4.90.1-1ubuntu1.10+esm5
Available with Ubuntu Pro
eximon4 4.90.1-1ubuntu1.10+esm5
Available with Ubuntu Pro
Ubuntu 16.04 LTS
exim4 4.86.2-2ubuntu2.6+esm8
Available with Ubuntu Pro
exim4-base 4.86.2-2ubuntu2.6+esm8
Available with Ubuntu Pro
eximon4 4.86.2-2ubuntu2.6+esm8
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-6939-1
CVE-2024-39929
Package Information:
https://launchpad.net/ubuntu/+source/exim4/4.97-4ubuntu4.1
https://launchpad.net/ubuntu/+source/exim4/4.95-4ubuntu2.6
https://launchpad.net/ubuntu/+source/exim4/4.93-13ubuntu1.12