#VU23908 Out-of-bounds write in TigerVNC - CVE-2019-15695

Vulnerability identifier: #VU23908

Vulnerability 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-2019-15695

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
TigerVNC
Web applications / Modules and components for CMS

Vendor: tigervnc.org

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to insufficient sanitization of PixelFormat. A remote attacker can trigger out-of-bounds write from "CMsgReader::readSetCursor" and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

TigerVNC: 0.0.90 - 1.10.0

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External links
https://github.com/CendioOssman/tigervnc/commit/05e28490873a861379c943bf616614b78b558b89
https://github.com/TigerVNC/tigervnc/releases/tag/v1.10.1
https://www.openwall.com/lists/oss-security/2019/12/20/2
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2020/03/23/klcert-20-008-remote-code-execution-on-tigervnc-version-prior-to-1-10-1-2/

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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.