CVE-2026-107614 — Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read

CVE-2026-107614

Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read PUBLISHED

Description (CNA)

An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to crash the server, and potentially read out-of-bounds memory, by causing a cursor shape with a width or height of zero to be processed on the DXGI capture path. The loop bound width - 1 wraps to 0xFFFFFFFF, producing an access roughly 4 GB beyond the 64 KB cursor buffer; a monochrome cursor of height 1 also becomes 0 because getCursorHeight() halves the height in place.

Affected (CNA)

Vendor / product	Versions
GlavSoft / TightVNC	affected 0 before 2.8.88

CWE

CWE-191, CWE-125

References

https://sourceforge.net/p/vnc-tight/bugs/1661/
https://www.tightvnc.com/whatsnew.php

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.