CVE-2026-107611
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.
How to fix
- GlavSoft TightVNC2.8.88 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| GlavSoft TightVNC | v < 2.8.88 | 2.8.88 |
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