CVE-2021-42785

Publication date 23 November 2021

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
tightvnc	26.04 LTS resolute	Not affected
	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Ignored end of standard support
	14.04 LTS trusty	Not affected

Notes

seth-arnold

Affects windows version

Severity score breakdown

CVSS version: CVSS v3.0

Base score 9.8 · Critical

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	9.8 · Critical
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H