CVE-2026-7831— UltraVNC 数字错误漏洞

UltraVNC viewer off-by-one stack overflow in ServerInit desktop name parsing

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Off-by-one错误

UltraVNC 数字错误漏洞

ultravnc是UltraVNC组织开源的一款用于Windows平台的开源远程终端控制软件。 UltraVNC 1.8.2.2及之前版本存在安全漏洞，该漏洞源于在RFB ServerInit消息处理程序中存在栈缓冲区差一错误，当服务器提供的名称长度正好为2024时会导致单字节NUL越界写入，可能触发拒绝服务。需要用户交互（将查看器连接到恶意服务器）。

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