LibVNC commit before d01e1bb4246323ba6fcee3b82ef1faa9b1dac82a contains a memory leak (CWE-655) in VNC server code, which allow an attacker to read stack memory and can be abused for information disclosure. Combined with another vulnerability, it can be used to leak stack memory and bypass ASLR. This attack appear to be exploitable via network connectivity. These vulnerabilities have been fixed in commit d01e1bb4246323ba6fcee3b82ef1faa9b1dac82a.
An issue was discovered in LibVNCServer through 0.9.11. rfbProcessClientNormalMessage() in rfbserver.c does not sanitize msg.cct.length, leading to access to uninitialized and potentially sensitive data or possibly unspecified other impact (e.g., an integer overflow) via specially crafted VNC packets.
The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer 0.9.9 and earlier does not properly handle attempts to send a large amount of ClientCutText data, which allows remote attackers to cause a denial of service (memory consumption or daemon crash) via a crafted message that is processed by using a single unchecked malloc.
The vino_server_client_data_pending function in vino-server.c in GNOME Vino 2.26.1, 2.32.1, 3.7.3, and earlier, and 3.8 when encryption is disabled, does not properly clear client data when an error causes the connection to close during authentication, which allows remote attackers to cause a denial of service (infinite loop, CPU and disk consumption) via multiple crafted requests during authentication.
Vino, possibly before 3.2, does not properly document that it opens ports in UPnP routers when the "Configure network to automatically accept connections" setting is enabled, which might make it easier for remote attackers to perform further attacks.
Vino before 2.99.4 can connect external networks contrary to the statement in the vino-preferences dialog box, which might make it easier for remote attackers to perform attacks.
The rfbSendFramebufferUpdate function in server/libvncserver/rfbserver.c in vino-server in Vino 2.x before 2.28.3, 2.32.x before 2.32.2, 3.0.x before 3.0.2, and 3.1.x before 3.1.1, when tight encoding is used, allows remote authenticated users to cause a denial of service (daemon crash) via crafted dimensions in a framebuffer update request that triggers an out-of-bounds read operation.
The rfbSendFramebufferUpdate function in server/libvncserver/rfbserver.c in vino-server in Vino 2.x before 2.28.3, 2.32.x before 2.32.2, 3.0.x before 3.0.2, and 3.1.x before 3.1.1, when raw encoding is used, allows remote authenticated users to cause a denial of service (daemon crash) via a large (1) X position or (2) Y position value in a framebuffer update request that triggers an out-of-bounds memory access, related to the rfbTranslateNone and rfbSendRectEncodingRaw functions.