CVE-2026-107614 Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read
A local authenticated user can crash the TightVNC Server or read out-of-bounds memory via an integer underflow in cursor shape processing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-107614?
CVE-2026-107614 is a medium-severity vulnerability in GlavSoft TightVNC, published on 8 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-107614?
How do I fix CVE-2026-107614?
No fix has been published for CVE-2026-107614 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-107614 being exploited?
There is no known exploitation of CVE-2026-107614 in the wild and no public exploit code.
Sources
Also known as GHSA-v6fq-v4c3-2qr7.