CVE-2014-6052

La función HandleRFBServerMessage en libvncclient/rfbproto.c en LibVNCServer 0.9.9 y anteriores no comprueba ciertos valores de retorno malloc, lo que permite a servidores remotos VNC causar una denegación de servicio (caída de la aplicación) o posiblemente ejecutar código arbitrario mediante la especificación de un tamaño de pantalla grande en un mensaje (1) FramebufferUpdate, (2) ResizeFrameBuffer, o (3) PalmVNCReSizeFrameBuffer.

A NULL pointer dereference flaw was found in LibVNCServer's framebuffer setup. A malicious VNC server could use this flaw to cause a VNC client to crash.

An integer overflow in liblzo before 2.07 allows attackers to cause a denial of service or possibly code execution in applications using performing LZO decompression on a compressed payload from the attacker. The libvncserver library is built with a bundled copy of minilzo, which is a part of liblzo containing the vulnerable code. A malicious VNC server can trigger incorrect memory management handling by advertising a large screen size parameter to the VNC client. This would result in multiple memory corruptions and could allow remote code execution on the VNC client. A malicious VNC client can trigger multiple DoS conditions on the VNC server by advertising a large screen size, ClientCutText message length and/or a zero scaling factor parameter. A malicious VNC client can trigger multiple stack-based buffer overflows by passing a long file and directory names and/or attributes when using the file transfer message feature.