Cyber Posture

CVE-2026-33516

Critical

Published: 17 April 2026

Published
17 April 2026
Modified
27 April 2026
KEV Added
—
Patch
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CVSS Score 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS Score 0.0011 28.4th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Description

xrdp is an open source RDP server. Versions through 0.10.5 contain an out-of-bounds read vulnerability during the RDP capability exchange phase. The issue occurs when memory is accessed before validating the remaining buffer length. A remote, unauthenticated attacker can trigger…

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this vulnerability by sending a specially crafted Confirm Active PDU. Successful exploitation could lead to a denial of service (process crash) or potential disclosure of sensitive information from the process memory. This issue has been fixed in version 0.10.6.

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match
prevent

Mandates timely patching of xrdp to version 0.10.6 or later to remediate the out-of-bounds read vulnerability during RDP capability exchange.

SI-10 Information Input Validation good match
prevent

Requires validation of incoming RDP Confirm Active PDU buffer lengths to prevent out-of-bounds memory access by remote attackers.

SI-16 Memory Protection good match
prevent

Implements memory protections such as ASLR and guard pages to mitigate denial-of-service crashes and sensitive information disclosure from out-of-bounds reads in xrdp.

Security SummaryAI

CVE-2026-33516 is an out-of-bounds read vulnerability (CWE-125) affecting xrdp, an open source Remote Desktop Protocol (RDP) server. The flaw exists in versions through 0.10.5 and occurs during the RDP capability exchange phase, where memory is accessed prior to validating the remaining buffer length. This high-severity issue, scored at CVSS 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H), was published on 2026-04-17.

A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted Confirm Active PDU to an affected xrdp instance. Successful exploitation may result in a denial of service via process crash or potential disclosure of sensitive information from the server's process memory, depending on the memory layout and contents at the time of the out-of-bounds access.

The xrdp project has addressed this vulnerability in version 0.10.6, as detailed in the release notes at https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6 and the security advisory at https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-rvh9-9wm3-28c7. Security practitioners should upgrade to 0.10.6 or later and consider network segmentation or firewalls to restrict RDP traffic until patching is complete.

Details

CWE(s)
CWE-125

Affected Products

neutrinolabs
xrdp
≤ 0.10.6

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Why these techniques?

Remote unauthenticated exploitation of a public-facing RDP server (xrdp) via crafted PDU enables initial access or lateral movement exploitation techniques (T1190, T1210) and application DoS via crash (T1499.004); potential memory disclosure aligns with exploitation impacts.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References