#VU29383 NULL pointer dereference in LibVNCServer - CVE-2020-14396

Vulnerability identifier: #VU29383

Vulnerability risk: Low

CVSSv4.0: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-14396

CWE-ID: CWE-476

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 perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in libvncclient/tls_openssl.c. A remote attacker can trick the victim to connect to a malicious server and perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.12

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External links
https://github.com/LibVNC/libvncserver/commit/33441d90a506d5f3ae9388f2752901227e430553
https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13

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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.