An OpenConnect security update has been released for Ubuntu Linux 18.04 LTS.

USN-4565-1: OpenConnect vulnerability

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Ubuntu Security Notice USN-4565-1
October 05, 2020

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

- Ubuntu 18.04 LTS

Summary:

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

Software Description:
- openconnect: An SSL VPN client

Details:

It was discovered that OpenConnect has a buffer overflow when a malicious
server uses HTTP chunked encoding with crafted chunk sizes. An attacker
could use it to provoke a denial of service (crash).

Update instructions:

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

Ubuntu 18.04 LTS:
libopenconnect5 7.08-3ubuntu0.18.04.2
openconnect 7.08-3ubuntu0.18.04.2

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

References:
  https://usn.ubuntu.com/4565-1
CVE-2019-16239

Package Information:
  https://launchpad.net/ubuntu/+source/openconnect/7.08-3ubuntu0.18.04.2