CVE-2021-42785

9.8 criticalEPSS 2.3%

Critical (9.8) in tightvnc tightvnc. EPSS 2.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

9.8 critical

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

EPSS: 2.3% chance of exploitation in the next 30 days; higher than 83% of CVEs (scores of 2026-10-31)
CWE: CWE-120
Published: 2021-11-23
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

tightvnc:tightvnc

References

https://www.tightvnc.com/whatsnew.php
https://www.tightvnc.com/whatsnew.php

Check your stack JSON