A TigerVNC security update has been released for Ubuntu Linux 20.04 ESM.

USN-5965-1: TigerVNC vulnerability

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Ubuntu Security Notice USN-5965-1
March 21, 2023

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

- Ubuntu 20.04 ESM

Summary:

TigerVNC could be made to expose sensitive information over the network.

Software Description:
- tigervnc: High-performance, platform-neutral implementation of VNC

Details:

It was discovered that TigerVNC mishandled TLS certificate exceptions. An
attacker could use this vulnerability to impersonate any server after a client
had added an exception and obtain sensitive information.

Update instructions:

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

Ubuntu 20.04 ESM:
tigervnc-common 1.10.1+dfsg-3ubuntu0.1+esm2
tigervnc-scraping-server 1.10.1+dfsg-3ubuntu0.1+esm2
tigervnc-standalone-server 1.10.1+dfsg-3ubuntu0.1+esm2

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

References:
  https://ubuntu.com/security/notices/USN-5965-1
CVE-2020-26117