CVE-2026-55238 xrdp: Malformed Confirm Active capability sets cause out-of-bounds reads
A remote unauthenticated attacker can cause a denial of service in xrdp by sending malformed RDP packets that trigger out-of-bounds memory reads.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55238?
CVE-2026-55238 is a medium-severity memory corruption vulnerability in neutrinolabs xrdp, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.
Weakness: CWE-126
Which versions are affected by CVE-2026-55238?
It affects 1 product.
Products include Neutrinolabs Xrdp.
How do I fix CVE-2026-55238?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-55238 being exploited?
There is no known exploitation of CVE-2026-55238 in the wild and no public exploit code.
Other vulnerabilities in neutrinolabs xrdp
- CVE-2026-41252 xrdp: lib_palette_update Heap Buffer Overflow & RCE
- CVE-2026-32105 xrdp: RDP MAC signature (dataSignature) never verified on receive — integrity bypass in non-TLS mode
- CVE-2026-44178 xrdp: Channel Data Forwarding Fixed-Size Buffer Overflow
- CVE-2026-32107 xrdp: Fail-open privilege drop in sesexec — child processes may execute as root if setuid fails
- CVE-2026-33689 xrdp: Pre-authentication out-of-bounds reads in channel parsers
Sources
Also known as DEBIAN-CVE-2026-55238, GHSA-mg8j-x9rw-9xv3, UBUNTU-CVE-2026-55238.