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.

The remote Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8476-1 advisory.

    It was discovered that xrdp incorrectly handled bounds checking when processing user domain information     during the connection sequence. An unauthenticated remote attacker could use this issue to cause xrdp to     crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2025-68670)

    It was discovered that xrdp did not correctly enforce the maximum number of login attempts configured by     the MaxLoginRetry parameter. A remote attacker could use this issue to perform an unlimited number of     login attempts. (CVE-2024-39917)

    It was discovered that xrdp did not perform bounds checking when accessing font glyphs. Since some of this     data is controllable by the user, a remote attacker could use this issue to cause xrdp to read out of     bounds. This issue only affected Ubuntu 24.04 LTS. (CVE-2023-42822)

    It was discovered that xrdp did not properly handle session establishment errors. A remote attacker could     use this issue to bypass OS-level session restrictions enforced by PAM, such as the maximum number of     concurrent sessions per user. This issue only affected Ubuntu 24.04 LTS. (CVE-2023-40184)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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.
    (CVE-2023-40184)

The remote Debian 11 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-4166 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4166-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                          Abhijith PA     May 16, 2025                                  https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : xrdp     Version        : 0.9.21.1-1~deb11u2     CVE ID         : CVE-2023-40184 CVE-2023-42822 CVE-2024-39917

    Several vulnerabilities were discovered in xrdp, a Remote Desktop     Protocol (RDP) server


    CVE-2023-40184

        improper handling of session establishment errors allows bypassing         OS-level session restrictions. The `auth_start_session` function         can return non-zero on PAM error which may result in in session         restrictions such as max concurrent sessions per user by PAM.

    CVE-2023-42822

        Access to the font glyphs in xrdp_painter.c is not bounds-checked         . Since some of this data is controllable by the user, this can         result in an out-of-bounds read within the xrdp executable. The         vulnerability allows an out-of-bounds read within a potentially         privileged process.

    CVE-2024-39917

        a vulnerability that allows attackers to make an infinite number         of login attempts. The number of max login attempts is supposed to         be limited by a configuration parameter `MaxLoginRetry` in         `/etc/xrdp/sesman.ini`. However, this mechanism was not         effectively working. As a result, xrdp allows an infinite number         of login attempts.

    For Debian 11 bullseye, these problems have been fixed in version     0.9.21.1-1~deb11u2.

    We recommend that you upgrade your xrdp packages.

    For the detailed security status of xrdp please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/xrdp

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES12 / SLES_SAP12 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4873-1 advisory.

    - CVE-2023-42822: Fixed unchecked access to font glyph info (bsc#1215803).
    - CVE-2023-40184: Fixed restriction bypass via improper session handling (bsc#1214805).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM / 22.04 ESM host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6474-1 advisory.

    It was discovered that xrdp incorrectly handled validation of client-supplied data, which could lead to     out-of-bounds reads. An attacker could possibly use this issue to crash the program or extract sensitive     information. (CVE-2022-23479, CVE-2022-23481, CVE-2022-23483, CVE-2023-42822)

    It was discovered that xrdp improperly handled session establishment errors. An attacker could potentially     use this issue to bypass the OS-level session restrictions by PAM. (CVE-2023-40184)

    It was discovered that xrdp incorrectly handled validation of client-supplied data, which could lead to     out-of-bounds writes. An attacker could possibly use this issue to cause memory corruption or execute     arbitrary code. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.
    (CVE-2022-23468)

    It was discovered that xrdp incorrectly handled validation of client-supplied data, which could lead to     out-of-bounds reads. An attacker could possibly use this issue to crash the program or extract sensitive     information. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.
    (CVE-2022-23480, CVE-2022-23482, CVE-2022-23484)

    It was discovered that xrdp incorrectly handled validation of client-supplied data, which could lead to     out-of-bounds reads. An attacker could possibly use this issue to crash the program or extract sensitive     information. This issue only affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2022-23477,     CVE-2022-23493)

    It was discovered that xrdp incorrectly handled validation of client-supplied data, which could lead to     out-of-bounds writes. An attacker could possibly use this issue to cause memory corruption or execute     arbitrary code. This issue only affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2022-23478)

    It was discovered that xrdp incorrectly handled validation of client-supplied data, which could lead to     out-of-bounds reads. An attacker could possibly use this issue to crash the program or extract sensitive     information. This issue only affected Ubuntu 22.04 LTS. (CVE-2022-23613)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 39 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-5134642a68 advisory.

    Release notes for xrdp v0.9.23 (2023/08/31)

    General announcements

     - Running xrdp and xrdp-sesman on separate hosts is still supported by this release, but is now     deprecated. This is not secure. A future v1.0 release will replace the TCP socket used between these     processes with a Unix Domain Socket, and then cross-host running will not be possible.

    Security fixes

     - CVE-2023-40184: Improper handling of session establishment errors allows bypassing OS-level session     restrictions (Reported by @gafusss)

    Bug fixes

     - Environment variables set by PAM modules are no longer restricted to around 250 characters (#2712)
     - X11 clipboard clients now no longer hang when requesting a clipboard format which isn't available     (#2767)

    New features

    No new features in this release.
    Internal changes

     - Introduce release tarball generation script (#2703)
     - cppcheck version used for CI bumped to 2.11 (#2738)

    Known issues

     - On-the-fly resolution change requires the Microsoft Store version of Remote Desktop client but     sometimes crashes on connect (#1869)
     - xrdp's login dialog is not relocated at the center of the new resolution after on-the-fly resolution     change happens (#1867)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2023:3830-1 advisory.

    - CVE-2023-40184: Fixed restriction bypass via improper session handling (bsc#1214805).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the c9ff1150-5d63-11ee-bbae-1c61b4739ac9 advisory.

  - 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.
    (CVE-2023-40184)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES12 / SLES_SAP12 host has a package installed that is affected by a vulnerability as referenced in the SUSE-SU-2023:3735-1 advisory.

    - CVE-2023-40184: Fixed restriction bypass via improper session handling (bsc#1214805).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Fedora 38 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-b1d585e148 advisory.

    Release notes for xrdp v0.9.23 (2023/08/31)

    General announcements

     - Running xrdp and xrdp-sesman on separate hosts is still supported by this release, but is now     deprecated. This is not secure. A future v1.0 release will replace the TCP socket used between these     processes with a Unix Domain Socket, and then cross-host running will not be possible.

    Security fixes

     - CVE-2023-40184: Improper handling of session establishment errors allows bypassing OS-level session     restrictions (Reported by @gafusss)

    Bug fixes

     - Environment variables set by PAM modules are no longer restricted to around 250 characters (#2712)
     - X11 clipboard clients now no longer hang when requesting a clipboard format which isn't available     (#2767)

    New features

    No new features in this release.
    Internal changes

     - Introduce release tarball generation script (#2703)
     - cppcheck version used for CI bumped to 2.11 (#2738)

    Known issues

     - On-the-fly resolution change requires the Microsoft Store version of Remote Desktop client but     sometimes crashes on connect (#1869)
     - xrdp's login dialog is not relocated at the center of the new resolution after on-the-fly resolution     change happens (#1867)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 37 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-40298f6951 advisory.

    Release notes for xrdp v0.9.23 (2023/08/31)

    General announcements

     - Running xrdp and xrdp-sesman on separate hosts is still supported by this release, but is now     deprecated. This is not secure. A future v1.0 release will replace the TCP socket used between these     processes with a Unix Domain Socket, and then cross-host running will not be possible.

    Security fixes

     - CVE-2023-40184: Improper handling of session establishment errors allows bypassing OS-level session     restrictions (Reported by @gafusss)

    Bug fixes

     - Environment variables set by PAM modules are no longer restricted to around 250 characters (#2712)
     - X11 clipboard clients now no longer hang when requesting a clipboard format which isn't available     (#2767)

    New features

    No new features in this release.
    Internal changes

     - Introduce release tarball generation script (#2703)
     - cppcheck version used for CI bumped to 2.11 (#2738)

    Known issues

     - On-the-fly resolution change requires the Microsoft Store version of Remote Desktop client but     sometimes crashes on connect (#1869)
     - xrdp's login dialog is not relocated at the center of the new resolution after on-the-fly resolution     change happens (#1867)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
322953	Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 : xrdp vulnerabilities (USN-8476-1)	Nessus	Ubuntu Local Security Checks	critical
427117	Alpine: multiple xrdp packages: security update to 0.9.23-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	medium
427117	Alpine: multiple xrdp packages: security update to 0.9.23-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	medium
236872	Debian dla-4166 : xrdp - security update	Nessus	Debian Local Security Checks	critical
187001	SUSE SLES12 Security Update : xrdp (SUSE-SU-2023:4873-1)	Nessus	SuSE Local Security Checks	medium
185416	Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM / 22.04 ESM : xrdp vulnerabilities (USN-6474-1)	Nessus	Ubuntu Local Security Checks	critical
185218	Fedora 39 : xrdp (2023-5134642a68)	Nessus	Fedora Local Security Checks	medium
407941	Alpine: multiple xrdp packages: security update to 0.9.23-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	medium
407941	Alpine: multiple xrdp packages: security update to 0.9.23-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	medium
182105	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xrdp (SUSE-SU-2023:3830-1)	Nessus	SuSE Local Security Checks	medium
182077	FreeBSD : xrdp -- Improper handling of session establishment errors allows bypassing OS-level session restrictions (c9ff1150-5d63-11ee-bbae-1c61b4739ac9)	Nessus	FreeBSD Local Security Checks	medium
181824	SUSE SLES12 Security Update : xrdp (SUSE-SU-2023:3735-1)	Nessus	SuSE Local Security Checks	medium
181205	Fedora 38 : xrdp (2023-b1d585e148)	Nessus	Fedora Local Security Checks	medium
181204	Fedora 37 : xrdp (2023-40298f6951)	Nessus	Fedora Local Security Checks	medium
401356	Alpine: multiple xrdp packages: security update to 0.9.22.1-r0 (deprecated)	Tenable Cloud Security	Alpine Linux Local Security Checks	medium
401356	Alpine: multiple xrdp packages: security update to 0.9.22.1-r0 (deprecated)	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	medium

Detections

Analytics

CVE-2023-40184

medium

Tenable Plugins

critical

medium

medium

critical

medium

critical

medium

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medium