Improper handling of session establishment errors in xrdp
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| neutrinolabs | xrdp | before 0.9.23 | 0.9.23 | Patch available | CNA |
- xrdp Vendorneutrinolabs Affected before 0.9.23 Fixed in 0.9.23 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:neutrinolabs:xrdp:*:*:*:*:*:*:*:* | before 0.9.23 | Vulnerable | neutrinolabs |
- cpe:2.3:a:neutrinolabs:xrdp:*:*:*:*:*:*:*:* Versions before 0.9.23 Vulnerable ·neutrinolabs
Remediation
- Fix · CNA xrdp (neutrinolabs) Fixed in 0.9.23
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2023-40184
References
Other 4
- https://github.com/neutrinolabs/xrdp/blame/9bbb2ec68f390504c32f2062847aa3d821a0089a/sesman/sesexec/session.c#L571C5-L571C19
- https://lists.fedoraproject.org/archives/list/[email protected]/message/U5IXMQODV3OIJ7DRQBUQV7PUKNT7SH36/
- https://lists.fedoraproject.org/archives/list/[email protected]/message/SOT237TIHTHPX5YNIWLVNINOEYC7WMG2/
- https://lists.fedoraproject.org/archives/list/[email protected]/message/URO3FKTFBPNKFARAQBEJLI4MH6YS35P5/
More neutrinolabs Xrdp vulnerabilities
- TI-2025-42163 xrdp improperly checks bounds of domain string length, which leads to Stack-based Buffer Overflow CVSS 3.1CRITICAL 9.8
- TI-2026-29860 xrdp: lib_palette_update Heap Buffer Overflow & RCE CVSS 3.1CRITICAL 9.8
- TI-2022-07540 Buffer Overflow in xrdp CVSS 3.1CRITICAL 9.8
- TI-2022-07539 Buffer Overflow occurs in xrdp CVSS 3.1CRITICAL 9.8
- TI-2022-07538 Out of Bound Write in xrdp CVSS 3.1CRITICAL 9.8
- TI-2022-07537 Buffer Overflow in xrdp CVSS 3.1CRITICAL 9.8
Sources
- CVE-2023-40184 · CVE Program
- CVE-2023-40184 · NVD
- FIRST EPSS
- CVE-2023-40184 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences