A libslirp security update has been released for Ubuntu Linux 20.04 LTS, 20.10, and 21.04.

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Ubuntu Security Notice USN-5009-1
July 15, 2021

libslirp vulnerabilities
==========================================================================

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

- Ubuntu 21.04
- Ubuntu 20.10
- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in libslirp.

Software Description:
- libslirp: General purpose TCP-IP emulator library

Details:

Qiuhao Li discovered that libslirp incorrectly handled certain header data
lengths. An attacker inside a guest could possibly use this issue to leak
sensitive information from the host. This issue only affected Ubuntu 20.04
LTS and Ubuntu 20.10. (CVE-2020-29129, CVE-2020-29130)

It was discovered that libslirp incorrectly handled certain udp packets. An
attacker inside a guest could possibly use this issue to leak sensitive
information from the host. (CVE-2021-3592, CVE-2021-3593, CVE-2021-3594,
CVE-2021-3595)

Update instructions:

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

Ubuntu 21.04:
libslirp0 4.4.0-1ubuntu0.1

Ubuntu 20.10:
libslirp0 4.3.1-1ubuntu0.1

Ubuntu 20.04 LTS:
libslirp0 4.1.0-2ubuntu2.2

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5009-1
CVE-2020-29129, CVE-2020-29130, CVE-2021-3592, CVE-2021-3593,
CVE-2021-3594, CVE-2021-3595

Package Information:
  https://launchpad.net/ubuntu/+source/libslirp/4.4.0-1ubuntu0.1
  https://launchpad.net/ubuntu/+source/libslirp/4.3.1-1ubuntu0.1
  https://launchpad.net/ubuntu/+source/libslirp/4.1.0-2ubuntu2.2