CVE-2026-107614
Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read
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.
- Record
CVE-2026-107614- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H - Weakness
- CWE-191, CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2026-94978
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.
- Record
EUVD-2026-94978- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-v6fq-v4c3-2qr7
An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft TightVNC Server for...
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.
- Record
GHSA-v6fq-v4c3-2qr7- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-107614- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H - Weakness
- CWE-125, CWE-191
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-107614
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.
- Record
UBUNTU-CVE-2026-107614- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-107614 is a medium vulnerability (CVSS 6.1) in Glavsoft Tightvnc, published October 8, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.11%, the 1st percentile. No source names a fixed version.