Out-of-Bounds Read in GlavSoft TightVNC Viewer for Windows (CVE-2026-107611)
Summary
Vulnerability in GlavSoft TightVNC Viewer for Windows (CVE-2026-107611). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-107611 has been found in GlavSoft TightVNC Viewer for Windows.
Risk of unauthorized operations or information disclosure. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "GlavSoft TightVNC Viewer for Windows CVE-2026-107611" on the vendor's site.
CVE-2026-107611 (GlavSoft TightVNC Viewer for Windows) — CWE-125 / CVSS v3 7.1
Attack vector: remote (network-reachable) / unauthenticated
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in GlavSoft TightVNC Viewer for Windows.
Check the vendor advisory for the affected versions of GlavSoft TightVNC Viewer for Windows.
Severity: High (CVSS 7.1/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで GlavSoft TightVNC Viewer for Windows を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web nvd.nist.gov
- web sourceforge.net
- web tightvnc.com
- web github.com
- web sourceforge.net