What’s Vulnerable › Vulnerabilities
CVE-2020-4044: Local users can perform a buffer overflow attack against the xrdp-sesman service and then impersonate it
- Severity: high (CVSS 7.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2020-06-30 · updated 2026-06-17
- Weakness: CWE-121
Description
The xrdp-sesman service before version 0.9.13.1 can be crashed by connecting over port 3350 and supplying a malicious payload. Once the xrdp-sesman process is dead, an unprivileged attacker on the server could then proceed to start their own imposter sesman service listening on port 3350. This will allow them to capture any user credentials that are submitted to XRDP and approve or reject arbitrary login credentials. For xorgxrdp sessions in particular, this allows an unauthorized user to hijack an existing session. This is a buffer overflow attack, so there may be a risk of arbitrary code execution as well.
Affected products
- neutrinolabs xrdp: before 0.9.13.1 — fixed in 0.9.13.1
How to fix
Upgrade to a fixed version: neutrinolabs xrdp 0.9.13.1. Check the vendor advisory for mitigations.
References
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00036.html
- http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00037.html
- https://github.com/neutrinolabs/xrdp/commit/0c791d073d0eb344ee7aaafd221513dc9226762c
- https://github.com/neutrinolabs/xrdp/releases/tag/v0.9.13.1
- https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-j9fv-6fwf-p3g4
- https://lists.debian.org/debian-lts-announce/2020/08/msg00015.html
- https://www.debian.org/security/2020/dsa-4737
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00036.html
- http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00037.html
- https://github.com/neutrinolabs/xrdp/commit/0c791d073d0eb344ee7aaafd221513dc9226762c
- https://github.com/neutrinolabs/xrdp/releases/tag/v0.9.13.1
- https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-j9fv-6fwf-p3g4
Get alerted when CVE-2020-4044 or the next vulnerability affects your stack