CVE-2026-33689: Neutrinolabs Xrdp Out of Bounds Read (CVSS 8.7)

xrdp is an open source RDP server. In versions 0.10.6 and prior, when an authenticated user session is initialized using the Xvnc backend over UNIX domain sockets, the Xvnc process is launched with insufficient authentication mechanisms. A local authenticated attacker could exploit this vulnerability to bypass intended session isolation, allowing them to unauthorizedly view or control the active desktop sessions of other users on the same system. Users using other backends, such as xorgxrdp or Xvnc over TCP sockets, are not affected. This issue has been fixed in version 0.10.6.1.

xrdp is an open source RDP server. Versions 0.10.6 and prior contain an integer overflow vulnerability when processing screen update messages within the vnc-any connection mode. A malicious remote VNC server can send crafted image dimensions that cause an integer overflow during memory buffer size calculation, resulting in an undersized allocation. Subsequent processing of the incoming image data using the original oversized parameters leads to an out-of-bounds read. An unauthenticated remote attacker could exploit this flaw to disclose sensitive information from the heap memory or cause a denial of service (DoS) via a process crash. This issue has been fixed in version 0.10.6.1.

xrdp is an open source RDP server. Versions through 0.10.5 have a heap-based buffer overflow in the EGFX (graphics dynamic virtual channel) implementation due to insufficient validation of client-controlled size parameters, allowing an out-of-bounds write via crafted PDUs. Pre-authentication exploitation can crash the process, while post-authentication exploitation may achieve remote code execution. This issue has been fixed in version 0.10.6. If users are unable to immediately update, they should run xrdp as a non-privileged user (default since 0.10.2) to limit the impact of successful exploitation.

xrdp is an open source RDP server. Versions through 0.10.5 contain an out-of-bounds read vulnerability during the RDP capability exchange phase. The issue occurs when memory is accessed before validating the remaining buffer length. A remote, unauthenticated attacker can trigger this vulnerability by sending a specially crafted Confirm Active PDU. Successful exploitation could lead to a denial of service (process crash) or potential disclosure of sensitive information from the process memory. This issue has been fixed in version 0.10.6.

xrdp is an open source RDP server. Versions through 0.10.5 contain a heap-based buffer overflow vulnerability in the NeutrinoRDP module. When proxying RDP sessions from xrdp to another server, the module fails to properly validate the size of reassembled fragmented virtual channel data against its allocated memory buffer. A malicious downstream RDP server (or an attacker capable of performing a Man-in-the-Middle attack) could exploit this flaw to cause memory corruption, potentially leading to a Denial of Service (DoS) or Remote Code Execution (RCE). The NeutrinoRDP module is not built by default. This vulnerability only affects environments where the module has been explicitly compiled and enabled. Users can verify if the module is built by checking for --enable-neutrinordp in the output of the xrdp -v command. This issue has been fixed in version 0.10.6.

xrdp is an open source RDP server. In versions through 0.10.5, xrdp does not implement verification for the Message Authentication Code (MAC) signature of encrypted RDP packets when using the "Classic RDP Security" layer. While the sender correctly generates signatures, the receiving logic lacks the necessary implementation to validate the 8-byte integrity signature, causing it to be silently ignored. An unauthenticated attacker with man-in-the-middle (MITM) capabilities can exploit this missing check to modify encrypted traffic in transit without detection. It does not affect connections where the TLS security layer is enforced. This issue has been fixed in version 0.10.6. If users are unable to immediately upgrade, they should configure xrdp.ini to enforce TLS security (security_layer=tls) to ensure end-to-end integrity.