[Windows] v15.21.4

Operating system: Windows

Version: 15.21.4

Release date: 2021-08-24

New features

• It's now possible to suppress sending chat messages to a device. This can be achieved by activating the setting for "Disable chat" in the options or via the registry (DisableChat). If disabling chat is activated, the chat tab is no longer visible.
• It is now possible to keep TeamViewer MSI installations up-to-date using automatic updates.
• It is now possible to inherit TeamViewer policies to managed devices via managed groups.
• A new way to display video in meetings is now available: Smart focus, which focuses on your face for better privacy control of your surroundings and more focused meetings!

Improvements

• Updated UI on media and list view in Meeting, for improved user experience.

Bug Fixes

• Fixed a bug that would cause the app not to reconnect if the internet connection was lost during a running meeting.
• Fixed a bug in the UI which prevented displaying the "What's New" window.
• CVE-2021-34858: Installations with existing TV recording files (TVS) were vulnerable to a problem in file parsing that could have allowed someone to execute arbitrary code and could have caused the binary to crash. User interaction as well as a third-party vulnerability would have been required for remote exploitation. We don’t have any indication of exploitation in the wild. Our thanks go to Kdot and the Trend Micro Zero Day Initiative for the responsible disclosure.
• CVE-2021-34859: In some circumstances, a problem in shared memory management could have caused the TeamViewer service to perform an out-of-bounds read. Access to the machine would have been required for exploitation. We don’t have any indication of exploitation in the wild. Our thanks go to Mat Powell and the Trend Micro Zero Day Initiative for the responsible disclosure.
• TeamViewer is installed by default in the protected Program Files directory. If a user intentionally had chosen to install it in a different location, someone would have been able to leverage a privilege escalation problem. Access to the machine would have been required for exploitation. We don’t have any indication of exploitation in the wild. Our thanks go to Maciej Miszczyk for the responsible disclosure.

Edit: this vulnerability has already been patched on August 24th, 2021, with v15.21.2 but due to misunderstanding, did not make it to the initial release notes. 

From a low-privileged user it is possible to modify shared memory and cause the TeamViewer service to perform an out-of-bounds read. The service then writes the data to the TeamViewer log file, where it can be read by the attacker.  

In this way, an attacker can disclose memory from the service process. This may be useful to an attacker as part of a larger exploit, perhaps ultimately resulting in execution of arbitrary code within the TeamViewer service running as SYSTEM. 

We don’t have any indication of exploitation in the wild. Our thanks go to Kharosx0 and the Trend Micro Zero Day Initiative for the responsible disclosure. This was tracked under CVE-2021-35005. This vulnerability has been patched with v15.21.2 on august 24th 2021.