CVE-2026-54538: xrdp: Pre-auth infinite loop via totalLength=0 in TS_SHARECONTROLHEADER

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-20 · updated 2026-10-24
Weakness: CWE-835

Description

xrdp is an open source RDP server. In versions 0.10.6 and prior, a n issue was discovered where the software fails to properly validate the totalLength field within the RDP protocol control header during packet reception. An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted packet that forces the xrdp process or thread into an infinite, CPU-bound loop. Because the internal pointer fails to advance and the deadlock prevention mechanism is bypassed for specific protocol data unit types, the process consumes excessive CPU resources indefinitely. This can render the xrdp service unavailable and potentially lead to system-wide resource exhaustion if multiple malicious connections are established. This issue has been fixed in version 0.10.6.1.

Affected products

neutrinolabs xrdp: before 0.10.6.1 — fixed in 0.10.6.1

How to fix

Upgrade to a fixed version: neutrinolabs xrdp 0.10.6.1. Check the vendor advisory for mitigations.

References

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