#VU29373 Buffer overflow in LibVNCServer


Published: 2020-06-30

Vulnerability identifier: #VU29373

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-20839

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
LibVNCServer
Server applications / Remote management servers, RDP, SSH

Vendor: LibVNC

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary when processing long socket filename in libvncclient/sockets.c in LibVNCServer. A remote attacker can rick the victim to connect to server using a specially crafted configuration file, trigger buffer overflow and execute arbitrary code on the target system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.12


External links
http://github.com/LibVNC/libvncserver/commit/3fd03977c9b35800d73a865f167338cb4d05b0c1
http://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.


Latest bulletins with this vulnerability