Vulnerability · Published Jul 20, 2026 · Assigned by GitHub_M
CVE-2026-55639xrdp: Out-of-bounds read in GCC Conference Create Request CS_SECURITY processing (xrdp_sec_process_mcs_data_CS_SECURITY)
Medium 5.3
In plain English
A medium-severity out-of-bounds read in xrdp from neutrinolabs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | xrdp | 0.9.21.1-1+deb12u3 | DEBIAN-CVE-2026-55639 |
| Debian:13 | xrdp | 0.10.1-3.1+deb13u2 | DEBIAN-CVE-2026-55639 |
| Debian:14 | xrdp | 0.10.6.1-2 | DEBIAN-CVE-2026-55639 |
| Ubuntu:22.04:LTS | xrdp | no fix listed | UBUNTU-CVE-2026-55639 |
| Ubuntu:24.04:LTS | xrdp | no fix listed | UBUNTU-CVE-2026-55639 |
| Ubuntu:25.10 | xrdp | no fix listed | UBUNTU-CVE-2026-55639 |
| Ubuntu:26.04:LTS | xrdp | no fix listed | UBUNTU-CVE-2026-55639 |
| Ubuntu:26.10 | xrdp | no fix listed | UBUNTU-CVE-2026-55639 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| neutrinolabs | xrdp | < 0.10.6.1 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc x_refsource_CONFIRM
- https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1 x_refsource_MISC