CVE-2026-55639 Information disclosure in xrdp
A remote unauthenticated attacker can read process memory via an out-of-bounds read in xrdp's security negotiation parsing.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55639?
CVE-2026-55639 is a medium-severity 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 parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1.
Weakness: CWE-125
Which versions are affected by CVE-2026-55639?
It affects 1 product.
Products include Neutrinolabs Xrdp.
How do I fix CVE-2026-55639?
Upgrade to a fixed version.
Is CVE-2026-55639 being exploited?
There is no known exploitation of CVE-2026-55639 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-2026-55639, GHSA-6g36-mxcf-r3gc, UBUNTU-CVE-2026-55639.