rdesktop through 1.9.0 contains a heap out-of-bounds read vulnerability in process_bmpcache2() in orders.c that allows malicious RDP servers to crash clients via crafted revision-2 bitmap cache orders. Attackers can send an uncompressed order with large width/height or an underflowing mode nibble and short payload, causing memcpy() reads past the receive buffer and denial of service.
https://hackmd.io/@haindpwn/rdesktop-bitmap-decompress-oob-read
https://github.com/rdesktop/rdesktop/pull/437
https://github.com/rdesktop/rdesktop/issues/436
Published: 2026-10-19
Updated: 2026-10-19
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
Severity: High
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 7.1
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.0031