CVE-2026-107614
Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read
GlavSoft TightVNC
CVSS
6.1MediumExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.10%Chance of exploitation activity in the next 30 days, higher than 1% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
- 2.8.88TightVNCCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
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.
Text from CVE List
Affected versions 1
- TightVNCaffected: all versions before 2.8.88CVE List