NULL pointer dereference in TightVNC - CVE-2019-15680

Vulnerability identifier: #VU22438

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-15680

CWE-ID: CWE-476

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in "zlib.c" in the "HandleZlibBPP" function. A remote attacker can trigger denial of service conditions via network connectivity.

TightVNC
Ubuntu
libvncclient1 (Ubuntu package)
libvncserver1 (Ubuntu package)

Install update from vendor's website.

libvncclient1 (Ubuntu package) - addressed in versions 0.9.10+dfsg-3ubuntu0.16.04.4, 0.9.11+dfsg-1.3ubuntu0.1, 0.9.11+dfsg-1ubuntu1.2, 0.9.12+dfsg-9ubuntu0.1
libvncserver1 (Ubuntu package) - addressed in versions 0.9.10+dfsg-3ubuntu0.16.04.4, 0.9.11+dfsg-1.3ubuntu0.1, 0.9.11+dfsg-1ubuntu1.2, 0.9.12+dfsg-9ubuntu0.1

• https://www.openwall.com/lists/oss-security/2018/12/10/5

• Multiple vulnerabilities in TightVNC
• Ubuntu update for libvncserver