#VU23903 Heap-based buffer overflow in TigerVNC - CVE-2019-15694

Vulnerability identifier: #VU23903

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-2019-15694

CWE-ID: CWE-122

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 execute arbitrary code on the target system.

The vulnerability exists due to the signedness error in processing MemOutStream. A remote attacker can trigger heap-based buffer overflow from DecodeManager::decodeRect and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable 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/0943c006c7d900dfc0281639e992791d6c567438
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/

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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.