CVE-2026-32105: xrdp: RDP MAC signature (dataSignature) never verified on receive — integrity bypass in non-TLS mode

Severity: high (CVSS 7.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-17 · updated 2026-10-26
Weakness: CWE-354

Description

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.

Affected products

neutrinolabs xrdp: before 0.10.6 — fixed in 0.10.6

How to fix

Upgrade to a fixed version: neutrinolabs xrdp 0.10.6. Check the vendor advisory for mitigations.

References

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