CVE-2026-107611
Out-of-bounds read in TightVNC Viewer ZRLE palette decoding
- State
- Published
- Severity
- 7.1 High
- Published
- Oct 8, 2026
- Updated
- Oct 8, 2026
- Reserved
- Oct 8, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.1 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H | securin |
Weaknesses
- CWE-125 Out-of-bounds Read
Affected Products
| Product | Versions |
|---|---|
TightVNCGlavSoft |
|
References
- TightVNC bug #1657issue-tracking
- TightVNC release notes (2.8.88)release-notespatch
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