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.
CVE-2026-107611
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-107611
TightVNC
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "GlavSoft",
"modules": [
"TightVNC Viewer (ZRLE decoder)"
],
"product": "TightVNC",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "2.8.88",
"versionType": "custom"
}
],
"platforms": [
"Windows"
],
"programFiles": [
"ZrleDecoder.cpp"
],
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "readPaletteRleTile()"
},
{
"name": "readPackedPaletteTile()"
}
]
}
]- Related CVEs
- CVE-2026-107611
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #12506 · Revision 1
- Added to Heist Feed
- Publisher date