CVE-2026-107611
Out-of-bounds read in TightVNC Viewer ZRLE palette decoding
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Out-of-bounds read in TightVNC Viewer ZRLE palette decoding
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.
- Record
CVE-2026-107611- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2026-94975
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.
- Record
EUVD-2026-94975- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-r575-8hw6-vfq3
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows...
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.
- Record
GHSA-r575-8hw6-vfq3- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
NVD
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.
- Record
CVE-2026-107611- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-107611
An out-of-bounds read vulnerability in the ZRLE decoder of GlavSoft TightVNC Viewer for Windows before 2.8.88 allows a malicious or compromised VNC server to read heap memory beyond the palette allocation and crash the viewer by sending ZRLE-encoded tiles whose palette indices exceed the declared palette size. readPaletteRleTile() and readPackedPaletteTile() use the attacker-supplied index to look up colours without validating it against the palette size; out-of-bounds heap data is copied into the framebuffer (garbled display) or the read faults, terminating the viewer.
- Record
UBUNTU-CVE-2026-107611- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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-2026-107611 is a high vulnerability (CVSS 7.1) 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 0.24%, the 14th percentile. No source names a fixed version.