CVE Watch9 jul 2026

CVE-2026-7831

UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConne

CVSS

7.6

Alto

EPSS

0.5%

p41

KEV

—

Exploit Today

0-100

Publicado: 1 jul 2026 · Última mod.: 9 jul 2026 · CWE-193 · CWE-787

EPSS · 30d

0.4%EPSS · 30 días0.5%

2026-07-012026-07-16

Descripción técnica

UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConnection.cpp, when the server-supplied nameLength equals exactly 2024 the code declares a 2024-byte stack buffer _dn[2024] and calls ReadString(_dn, 2024). ReadString writes the NUL terminator at buf[length], i.e., _dn[2024], one byte past the end of the stack buffer. A malicious VNC server can trigger this condition by advertising a desktop name of length 2024 in its ServerInit message. On release builds without stack canaries the single-byte NUL overwrite adjacent stack data. On builds with /GS stack protection the canary is corrupted and the process terminates, resulting in denial of service. User interaction (connecting the viewer to the malicious server) is required.

Referencias oficiales

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