CVE-2026-59691

A heap buffer overflow vulnerability was found in GStreamer's rfbsrc plugin. When a client connects to a malicious RFB/VNC server that advertises a 16bpp framebuffer and sends Hextile-encoded updates, the Hextile background fill path writes 32-bit pixel values into a buffer allocated for 16-bit...

EUVD-2026-42569

A heap buffer overflow vulnerability was found in GStreamer's rfbsrc plugin. When a client connects to a malicious RFB/VNC server that advertises a 16bpp framebuffer and sends Hextile-encoded updates, the Hextile background fill path writes 32-bit pixel values into a buffer allocated for 16-bit...

Out-of-bounds Write

Overview Affected versions of this package are vulnerable to Out-of-bounds Write in the rfbsrc process when connecting to a malicious RFB/VNC server that advertises a 16bpp framebuffer and sends Hextile-encoded updates. An attacker can cause a process crash or potentially corrupt memory by...

CVE-2026-7838

UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB protocol failure-response parsing path. In vncviewer/ClientConnection.cpp, the 4-byte network-supplied reasonLen field type CARD32 is passed as reasonLen+1 to CheckBufferSize. Because both...

CVE-2026-7838 UltraVNC viewer heap buffer overflow via integer overflow in RFB connection-failure reason length

UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB protocol failure-response parsing path. In vncviewer/ClientConnection.cpp, the 4-byte network-supplied reasonLen field type CARD32 is passed as reasonLen+1 to CheckBufferSize. Because both...

EUVD-2026-40884

UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB protocol failure-response parsing path. In vncviewer/ClientConnection.cpp, the 4-byte network-supplied reasonLen field type CARD32 is passed as reasonLen+1 to CheckBufferSize. Because both...

DEBIAN-CVE-2026-52720

A heap buffer overflow vulnerability was found in GStreamer's librfb RFB/VNC client. The rectangle bounds check incorrectly validates area rather than individual dimensions, allowing a malicious VNC server to send a rectangle that extends beyond the framebuffer. A remote attacker could set up a...

CVE-2026-52720

A heap buffer overflow vulnerability was found in GStreamer's librfb RFB/VNC client. The rectangle bounds check incorrectly validates area rather than individual dimensions, allowing a malicious VNC server to send a rectangle that extends beyond the framebuffer. A remote attacker could set up a...

OESA-2026-2490 libvncserver security update

libvncserver is a set of programs using the RFB Remote Frame Buffer protocol. They are designed to "export" a frame buffer via net: you set up a server and can connect to it via VNC viewers. If the server supports WebSockets which LibVNCServer does, you can also connect using an in-browser VNC...

CVE-2021-41380

RealVNC Viewer 6.21.406 allows remote VNC servers to cause a denial of service application crash via crafted RFB protocol data. NOTE: It is asserted that this issue requires social engineering a user into connecting to a fake VNC Server. The VNC Viewer application they are using will then hang,...

libvncserver: uninitialized memory contents are vulnerable to Information Leak

An issue was discovered in LibVNCServer before 0.9.13. There is an information leak of uninitialized memory contents in the libvncclient/rfbproto.c ConnectToRFBRepeater function...

libvncserver: Improper input sanitization in rfbProcessClientNormalMessage in rfbserver.c

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...