CVE-2026-107614
Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read
- State
- Published
- Severity
- 6.1 Medium
- Published
- Oct 8, 2026
- Updated
- Oct 8, 2026
- Reserved
- Oct 8, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.1 Medium | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H | securin |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
TightVNCGlavSoft |
|
References
- TightVNC bug #1661issue-tracking
- TightVNC release notes (2.8.88)release-notespatch
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