USN-4066-1: libmspack vulnerability

18 July 2019

libmspack vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS


libmspack could be made to expose sensitive information if it received a specially crafted CHM file.

Software Description

  • libmspack - library for Microsoft compression formats


It was discovered that libmspack incorrectly handled certain CHM files. A remote attacker could possibly use this issue to access sensitive information.

Update instructions

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

Ubuntu 18.04 LTS
libmspack0 - 0.6-3ubuntu0.3
Ubuntu 16.04 LTS
libmspack0 - 0.5-1ubuntu0.16.04.4

To update your system, please follow these instructions:

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