What’s Vulnerable › Vulnerabilities
CVE-2023-40184: Improper handling of session establishment errors in xrdp
- Severity: medium (CVSS 6.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.9% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2023-08-30 · updated 2026-06-17
- Weakness: CWE-755
Description
xrdp is an open source remote desktop protocol (RDP) server. In versions prior to 0.9.23 improper handling of session establishment errors allows bypassing OS-level session restrictions. The `auth_start_session` function can return non-zero (1) value on, e.g., PAM error which may result in in session restrictions such as max concurrent sessions per user by PAM (ex ./etc/security/limits.conf) to be bypassed. Users (administrators) don't use restrictions by PAM are not affected. This issue has been addressed in release version 0.9.23. Users are advised to upgrade. There are no known workarounds for this issue.
Affected products
- neutrinolabs xrdp: before 0.9.23 — fixed in 0.9.23
How to fix
Upgrade to a fixed version: neutrinolabs xrdp 0.9.23. Check the vendor advisory for mitigations.
References
- https://github.com/neutrinolabs/xrdp/blame/9bbb2ec68f390504c32f2062847aa3d821a0089a/sesman/sesexec/session.c#L571C5-L571C19
- https://github.com/neutrinolabs/xrdp/commit/a111a0fdfe2421ef600e40708b5f0168594cfb23
- https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-f489-557v-47jq
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SOT237TIHTHPX5YNIWLVNINOEYC7WMG2/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U5IXMQODV3OIJ7DRQBUQV7PUKNT7SH36/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/URO3FKTFBPNKFARAQBEJLI4MH6YS35P5/
- https://github.com/neutrinolabs/xrdp/blame/9bbb2ec68f390504c32f2062847aa3d821a0089a/sesman/sesexec/session.c#L571C5-L571C19
- https://github.com/neutrinolabs/xrdp/commit/a111a0fdfe2421ef600e40708b5f0168594cfb23
- https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-f489-557v-47jq
- https://lists.debian.org/debian-lts-announce/2025/05/msg00018.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SOT237TIHTHPX5YNIWLVNINOEYC7WMG2/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U5IXMQODV3OIJ7DRQBUQV7PUKNT7SH36/
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