Out-of-bounds read in xrdp - CVE-2026-55639
Published: July 2, 2026
Vulnerability identifier: #VU136783
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-55639
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: neutrinolabs
Affected software:
xrdp
xrdp
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to out-of-bounds read in the Client Security Data parser when parsing the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. A remote attacker can send a specially crafted RDP packet containing malformed data to disclose sensitive information.
The issue may read a small number of bytes beyond the declared data block boundary during the initial capability and security negotiation phase.
How to mitigate CVE-2026-55639
Install security update from vendor's website.