USN-4407-1: LibVNCServer vulnerabilities
1 July 2020
Several security issues were fixed in LibVNCServer.
Releases
Packages
- libvncserver - vnc server library
Details
It was discovered that LibVNCServer incorrectly handled decompressing data. An
attacker could possibly use this issue to cause LibVNCServer to crash,
resulting in a denial of service. (CVE-2019-15680)
It was discovered that an information disclosure vulnerability existed in
LibVNCServer when sending a ServerCutText message. An attacker could possibly
use this issue to expose sensitive information. This issue only affected
Ubuntu 19.10, Ubuntu 18.04 LTS, and Ubuntu 16.04 LTS. (CVE-2019-15681)
It was discovered that LibVNCServer incorrectly handled cursor shape updates.
If a user were tricked in to connecting to a malicious server, an attacker
could possibly use this issue to cause LibVNCServer to crash, resulting in a
denial of service, or possibly execute arbitrary code. This issue only
affected Ubuntu 19.10, Ubuntu 18.04 LTS, and Ubuntu 16.04 LTS.
(CVE-2019-15690, CVE-2019-20788)
It was discovered that LibVNCServer incorrectly handled decoding WebSocket
frames. An attacker could possibly use this issue to cause LibVNCServer to
crash, resulting in a denial of service, or possibly execute arbitrary code.
This issue only affected Ubuntu 19.10, Ubuntu 18.04 LTS, and Ubuntu 16.04 LTS.
(CVE-2017-18922)
Update instructions
The problem can be corrected by updating your system to the following package versions:
Ubuntu 20.04
Ubuntu 19.10
Ubuntu 18.04
Ubuntu 16.04
After a standard system update you need to restart LibVNCServer to make
all the necessary changes.