PT-2021-4944 · Tightvnc · Tightvnc Viewer

Eugene Lim · Published 2021-09-17 · Updated 2021-11-29 · CVE-2021-42785

Positive Technologies (AI Summary)

CVSS v2.0

10

Critical

Base vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Name of the Vulnerable Software and Affected Versions TightVNC Viewer (affected versions not specified)

Description The issue is related to a Buffer Overflow vulnerability in the tvnviewer.exe component of TightVNC Viewer. This vulnerability allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server. The vulnerability is caused by a lack of size checking for input data, which can be exploited by a remote attacker to execute arbitrary code.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Buffer Overflow

Weakness Enumeration

CWE-120

Related Identifiers

BDU:2021-05697

CVE-2021-42785

Affected Products

Tightvnc Viewer

References · 8

• https://osv.dev/vulnerability/UBUNTU-CVE-2021-42785 · Vendor Advisory
• https://tightvnc.com/whatsnew.php · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-42785 · Security Note
• https://cve.org/CVERecord?id=CVE-2021-42785 · Security Note
• https://osv.dev/vulnerability/CVE-2021-42785 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-42785 · Vendor Advisory
• https://bdu.fstec.ru/vul/2021-05697 · Security Note
• https://t.me/cvenotify/23898 · Telegram Post