A GMP security update has been released for Ubuntu Linux 16.04 ESM, 18.04 LTS, and 20.04 LTS.

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Ubuntu Security Notice USN-5672-1
October 12, 2022

GMP vulnerability
==========================================================================

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

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM

Summary:

GMP could be made to crash if it received specially crafted
input.

Software Description:
- gmp: Multiprecision arithmetic library developers tools

Details:

It was discovered that GMP did not properly manage memory
on 32-bit platforms when processing a specially crafted
input. An attacker could possibly use this issue to cause
applications using GMP to crash, resulting in a denial of
service.

Update instructions:

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

Ubuntu 20.04 LTS:
libgmp-dev 2:6.2.0+dfsg-4ubuntu0.1
libgmp10 2:6.2.0+dfsg-4ubuntu0.1
libgmpxx4ldbl 2:6.2.0+dfsg-4ubuntu0.1

Ubuntu 18.04 LTS:
libgmp-dev 2:6.1.2+dfsg-2ubuntu0.1
libgmp10 2:6.1.2+dfsg-2ubuntu0.1
libgmpxx4ldbl 2:6.1.2+dfsg-2ubuntu0.1

Ubuntu 16.04 ESM:
libgmp-dev 2:6.1.0+dfsg-2ubuntu0.1~esm1
libgmp10 2:6.1.0+dfsg-2ubuntu0.1~esm1
libgmpxx4ldbl 2:6.1.0+dfsg-2ubuntu0.1~esm1

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

References:
https://ubuntu.com/security/notices/USN-5672-1
CVE-2021-43618

Package Information:
https://launchpad.net/ubuntu/+source/gmp/2:6.2.0+dfsg-4ubuntu0.1
https://launchpad.net/ubuntu/+source/gmp/2:6.1.2+dfsg-2ubuntu0.1