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.
CVSS Details
- CVSS 4.0 Base Score: 9.3 (CRITICAL)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 7.7
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade xrdp | Apr 24, 2026 | Apr 17, 2026 |
| Debian | — | Upgrade xrdp | Aug 30, 2026 | Aug 30, 2026 |
| Freebsd | — | Upgrade xrdp | Apr 20, 2026 | Apr 18, 2026 |
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