#VU23907 Heap-based buffer overflow in TigerVNC - CVE-2019-15693

Vulnerability identifier: #VU23907

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-2019-15693

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 a boundary error in "TightDecoder::FilterGradient". A remote attacker can trigger heap-based buffer overflow 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/b4ada8d0c6dac98c8b91fc64d112569a8ae5fb95
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-20-007-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.