A noVNC security update has been released for Ubuntu Linux 16.04 LTS.

USN-4522-1: noVNC vulnerability

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Ubuntu Security Notice USN-4522-1
September 21, 2020

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

- Ubuntu 16.04 LTS

Summary:

noVNC could be made to execute arbitrary code.

Software Description:
- novnc: HTML5 VNC client - daemon and programs

Details:

It was discovered that noVNC did not properly manage certain messages,
resulting in the remote VNC server injecting arbitrary HTML into the
noVNC web page. An attacker could use this issue to conduct cross-site
scripting (XSS) attacks. (CVE-2017-18635)

Update instructions:

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

Ubuntu 16.04 LTS:
novnc
1:0.4+dfsg+1+20131010+gitf68af8af3d-4+deb8u1build0.16.04.1
python-novnc
1:0.4+dfsg+1+20131010+gitf68af8af3d-4+deb8u1build0.16.04.1

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

References:
  https://usn.ubuntu.com/4522-1
CVE-2017-18635

Package Information:

  https://launchpad.net/ubuntu/+source/novnc/1:0.4+dfsg+1+20131010+gitf68af8af3d-4+deb8u1build0.16.04.1