Red Hat Enterprise Linux 7 update for libvncserver

1) Out-of-bounds write

EUVDB-ID: #VU30157

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2017-18922

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A malicious attacker could exploit this by sending specially crafted WebSocket frames to a server, causing a heap-based buffer overflow.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

libvncserver (Red Hat package): 0.9.9-12.el7_5 - 0.9.9-13.el7_6

CPE2.3

• cpe:2.3:a:red_hat:libvncserver_redhat_package:0.9.9-12.el7_5:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:a:red_hat:libvncserver_redhat_package:0.9.9-13.el7_6:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2020:3281

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.