CVE-2026-107611

Out-of-bounds read in TightVNC Viewer ZRLE palette decoding

HIGH
7.1
CVSS Score
Published: October 8, 2026 at 01:39 PM UTC
Updated: October 8, 2026 at 09:10 PM UTC
1 product affected across 1 vendorTightvnc

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Severity
HIGH7.1
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0 ≤ v < 2.8.880

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

Issue Tracking
Source: cverecord
https://sourceforge.net/p/vnc-tight/bugs/1657/
Release NotesPatch
Source: cverecord
https://www.tightvnc.com/whatsnew.php

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.1HIGHsecurin
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-125

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