PT-2016-3303 · Libvncserver Team+3 · Libvncserver+3

Josef Gajdusek · Published 2016-11-24 · Updated 2020-10-23 · CVE-2016-9942

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions LibVNCServer versions prior to 0.9.11

Description The issue is related to a heap-based buffer overflow in the ultra.c component of LibVNCServer. This can be exploited by remote servers via a crafted FramebufferUpdate message with the Ultra type tile, where the LZO payload decompressed length exceeds the tile dimensions. The exploitation may lead to a denial of service, causing the application to crash, or possibly allow the execution of arbitrary code. The vulnerability can also be used to gain unauthorized access to confidential data.

Recommendations For versions prior to 0.9.11, update to version 0.9.11 or later to resolve the issue. As a temporary workaround, consider restricting access to the ultra.c component until a patch is available. Avoid using the Ultra type tile in FramebufferUpdate messages until the issue is resolved.

Fix

DoS

Buffer Overflow

Weakness Enumeration

CWE-119

Related Identifiers

ALT-PU-2017-2266

BDU:2020-00674

CVE-2016-9942

DLA-1979-1

DLA-777-1

DSA-3753-1

MGASA-2017-0027

OPENSUSE-SU-2018_0851-1

SUSE-SU-2017:0104-1

SUSE-SU-2017:0519-1

SUSE-SU-2017:0622-1

SUSE-SU-2018:0830-1

USN-3171-1

USN-4587-1

Affected Products

Alt Linux

Libvncserver

Suse

Ubuntu

References · 63

• https://ubuntu.com/security/CVE-2018-20019 · Vendor Advisory
• https://ubuntu.com/security/CVE-2018-20024 · Vendor Advisory
• https://osv.dev/vulnerability/DLA-1979-1 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2018:0830-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2016-9941 · Vendor Advisory
• https://ubuntu.com/security/CVE-2018-20749 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2016-9942 · Vendor Advisory
• https://osv.dev/vulnerability/USN-3171-1 · Vendor Advisory
• https://usn.ubuntu.com/4587-1 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-3171-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2018-20021 · Vendor Advisory
• https://osv.dev/vulnerability/DSA-3753-1 · Vendor Advisory
• https://advisories.mageia.org/MGASA-2017-0027.html · Security Note
• https://ubuntu.com/security/CVE-2014-6055 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2017:0104-1 · Vendor Advisory