FreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them. Attackers can send incompatible protocol requests, receive negotiation failures, then complete TLS handshake and enter RDSTLS to bypass pre-authentication transport restrictions.
FreeRDP before 3.31.0 contains an out-of-bounds read vulnerability in the rdpdr_dump_packet function due to 32-bit unsigned integer wraparound in buffer bounds validation. A malicious RDP server can send a crafted RDPDR packet with computerNameLen set to 0xFFFFFFF0 to bypass bounds checks and trigger memory reads past the packet buffer, causing client crashes or heap disclosure in logs.
FreeRDP versions 3.0.0 through 3.30.0 (before 3.31.0) transmit uninitialized heap memory in Save Session Info PDU reserved padding fields. Three PDU writers in libfreerdp/core/info.c (rdp_write_logon_info_v2, rdp_write_logon_info_plain, and rdp_write_logon_info_ex) use Stream_Seek instead of Stream_Zero for reserved pad bytes (up to 576 bytes), leaving previously freed heap contents in the outgoing PDU. Because the send buffer is allocated with malloc (not zeroed), stale heap data — which may include cleartext credentials from prior sessions — can be sent to the receiving peer. FreeRDP-based servers using rdpUpdate::SaveSessionInfo and freerdp-proxy (which forwards these PDUs) are affected, allowing disclosure of server/proxy process memory to a downstream client.
FreeRDP before 3.31.0 contains a heap out-of-bounds read vulnerability in the general_ChromaV1ToYUV444 function during AVC444 chroma plane reconstruction. A malicious RDP server can craft a RFX_AVC444_BITMAP_STREAM with specific frame geometry to trigger an out-of-bounds memory read past the allocated luma plane.
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.30.0, FreeRDP server-side RDSTLS in libfreerdp/core/rdstls.c accepts an attacker-supplied RDSTLS_TYPE_CAPABILITIES PDU while rdstls_server_authenticate is waiting for RDSTLS_TYPE_AUTHREQ, leaving resultCode at RDSTLS_RESULT_SUCCESS and allowing a remote unauthenticated client to bypass the RedirectionGuid, username, domain, or password checks. This issue is fixed in version 3.30.0.
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.30.0, FreeRDP's winpr/libwinpr/sspi/Kerberos/kerberos.c kerberos_DecryptMessage function fails to bound the peer-controlled GSS Wrap-token EC field before using it with RRC in IOV pointer offsets, allowing a malicious RDP peer to trigger out-of-bounds reads and in-place writes during CredSSP/NLA Kerberos decryption. This issue is fixed in version 3.30.0.
FreeRDP before 3.30.0 (<= 3.29.0) contains a heap-based buffer overflow in the Windows clipboard client's CliprdrStream_Read function (client/Windows/wf_cliprdr.c). When an OLE paste consumer (e.g. explorer.exe) calls IStream::Read with a fixed-size buffer of cb bytes, CliprdrStream_Read requests file contents from the RDP server and then copies the response into the caller's buffer using the server-supplied length (req_fsize) instead of cb. A malicious or compromised RDP server can return an oversized CB_FILECONTENTS_RESPONSE, causing an out-of-bounds write of attacker-controlled data into the paste consumer's heap buffer when a user pastes server-offered clipboard file contents.
FreeRDP before 3.29.0 contains integer overflow vulnerabilities in the audio input redirection channel (audin) across ALSA, sndio, WinMM, and OpenSL ES backends that fail to validate the FramesPerPacket parameter from RDP servers. Attackers can supply a malicious FramesPerPacket value causing allocation size wraparound, resulting in heap-based buffer overflow on ALSA or denial of service on all platforms.
FreeRDP Windows client before 3.29.0 contains a heap buffer overflow vulnerability in the clipboard virtual channel when processing CLIPRDR_FILE_CONTENTS_RESPONSE PDUs without validating the server-provided size against the destination buffer. A malicious RDP server can send a response with a data payload significantly larger than requested, causing arbitrary heap memory corruption that may enable remote code execution when a user performs a paste operation.
FreeRDP before 3.29.0 contains a client-side heap use-after-free in the async update message proxy for WINDOW_ICON_ORDER when AsyncUpdate is enabled (e.g. xfreerdp /async-update). In update_message_WindowIcon() a shallow CopyMemory() overwrites a freshly allocated lParam->iconInfo with the parser-owned windowIcon->iconInfo pointer. After the parser callback returns, update_recv_window_info_order() frees window_icon.iconInfo, but the queued async message still retains and later dispatches that stale pointer. A malicious or compromised RDP server sending a crafted RAIL Window Alternate Secondary Order with WINDOW_ORDER_ICON can trigger use-after-free, leading to memory corruption and client crash.