Ubuntu 26.04 LTS Exim Major DoS Vulnerability Risk USN-8270-1

ubuntu

May 12, 2026

Exim could be made to crash or run programs if it received specially crafted network traffic.

Summary

Exim could be made to crash or run programs if it received specially

crafted network traffic.

Software Description:

- exim4: Exim is a mail transport agent

Details:

It was discovered that Exim incorrectly handled BDAT body parsing. A remote

attacker could use this issue to cause Exim to crash, resulting in a denial

of service, or possibly execute arbitrary code.

Topics Covered

security advisory denial of service exim Ubuntu important program crash

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  exim4                           4.99.1-1ubuntu1.2
  exim4-base                      4.99.1-1ubuntu1.2
  eximon4                         4.99.1-1ubuntu1.2

Ubuntu 25.10
  exim4                           4.98.2-1ubuntu2.2
  exim4-base                      4.98.2-1ubuntu2.2
  eximon4                         4.98.2-1ubuntu2.2

Ubuntu 24.04 LTS
  exim4                           4.97-4ubuntu4.5
  exim4-base                      4.97-4ubuntu4.5
  eximon4                         4.97-4ubuntu4.5

Ubuntu 22.04 LTS
  exim4                           4.95-4ubuntu2.8
  exim4-base                      4.95-4ubuntu2.8
  eximon4                         4.95-4ubuntu2.8

In general, a standard system update will make all the necessary changes.