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KLCERT-20-005: Remote Code Execution on TigerVNC version prior to 1.10.1

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KL-IDS KLCERT-20-005
CVE-IDS CVE-2019-15691
Publication date 2020.03.23
Researcher Pavel Cheremushkin, Kaspersky ICS CERT
Description TigerVNC version prior to 1.10.1 is vulnerable to stack use-after-return, which occurs due to incorrect usage of stack memory in ZRLEDecoder. If decoding routine would throw an exception, ZRLEDecoder may try to access stack variable, which has been already freed during the process of stack unwinding. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity.
Impact Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code.
Severity
CVSS v3 Base Score: 8.8
Vector CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
Exploitability Remotely
Difficulty Low
User interaction None
Existence of exploit Unknown
Affected products
Affected products TigerVNC version prior to 1.10.1
Mitigation
Vendor mitigation Update current version of TigerVNC.
Timeline Nov 2019 – Vulnerabilities reported
Dec 2019 – Vendor releases patch
Dec 2019 – Advisory published