# CVE-2020-4044: Local users can perform a buffer overflow attack against the xrdp-sesman service and then impersonate it > Local attackers can crash the xrdp-sesman service via buffer overflow and impersonate it to steal credentials or hijack sessions. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 30 Jun 2020 - **Updated:** 4 Aug 2024 - **Also known as:** DEBIAN-CVE-2020-4044, DLA-2319-1, DSA-4737-1, GHSA-j9fv-6fwf-p3g4, MGASA-2021-0016, SUSE-SU-2020:1918-1, SUSE-SU-2020:1933-1, SUSE-SU-2020:1991-1, SUSE-SU-2020:2142-1, UBUNTU-CVE-2020-4044, USN-6469-1, openSUSE-SU-2020:0999-1, openSUSE-SU-2020:1200-1 ## What is CVE-2020-4044? CVE-2020-4044 is a high-severity memory corruption vulnerability in neutrinolabs xrdp, published on 30 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. Weakness: CWE-121 (Stack-based Buffer Overflow) ## Which versions are affected by CVE-2020-4044? It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `xrdp` | SUSE:Enterprise Storage 5 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:HPE Helion OpenStack 8 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:Linux Enterprise High Performance Computing 15-ESPOS | All versions | 0.9.6-4.8.1 | | `xrdp` | SUSE:Linux Enterprise High Performance Computing 15-LTSS | All versions | 0.9.6-4.8.1 | | `xrdp` | SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 0.9.6-4.8.1 | | `xrdp` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 0.9.13.1-4.3.1 | | `xrdp` | SUSE:Linux Enterprise Server 12 SP3-BCL | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:Linux Enterprise Server 12 SP4-LTSS | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 0.9.10-3.3.1 | | `xrdp` | SUSE:Linux Enterprise Server 15-LTSS | All versions | 0.9.6-4.8.1 | | `xrdp` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 0.9.10-3.3.1 | | `xrdp` | SUSE:Linux Enterprise Server for SAP Applications 15 | All versions | 0.9.6-4.8.1 | | `xrdp` | SUSE:OpenStack Cloud 8 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:OpenStack Cloud 9 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:OpenStack Cloud Crowbar 8 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | SUSE:OpenStack Cloud Crowbar 9 | All versions | 0.9.0~git.1456906198.f422461-21.27.1 | | `xrdp` | openSUSE:Leap 15.1 | All versions | 0.9.6-lp151.4.6.1 | | `xrdp` | openSUSE:Leap 15.2 | All versions | 0.9.13.1-lp152.3.3.1 | Products: Neutrinolabs Xrdp. ## How do I fix CVE-2020-4044? Upgrade to a fixed version. ## Is CVE-2020-4044 being exploited? There is no known exploitation of CVE-2020-4044 in the wild and no public exploit code. ## Other vulnerabilities in neutrinolabs xrdp - [CVE-2026-41252](https://insights.sbomify.com/CVE-2026-41252/): xrdp: lib_palette_update Heap Buffer Overflow & RCE (critical 9.8) - [CVE-2026-32105](https://insights.sbomify.com/CVE-2026-32105/): xrdp: RDP MAC signature (dataSignature) never verified on receive — integrity bypass in non-TLS mode (critical 9.3) - [CVE-2026-44178](https://insights.sbomify.com/CVE-2026-44178/): xrdp: Channel Data Forwarding Fixed-Size Buffer Overflow (high 8.8) - [CVE-2026-32107](https://insights.sbomify.com/CVE-2026-32107/): xrdp: Fail-open privilege drop in sesexec — child processes may execute as root if setuid fails (high 8.8) - [CVE-2026-33689](https://insights.sbomify.com/CVE-2026-33689/): xrdp: Pre-authentication out-of-bounds reads in channel parsers (high 8.7) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-4044 and fix it if it is affected. What it is: CVE-2020-4044 is a high-severity memory corruption vulnerability in neutrinolabs xrdp, published on 30 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2020-4044 in the wild and no public exploit code. Affected product: neutrinolabs xrdp. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2020-4044/ (Markdown: https://insights.sbomify.com/CVE-2020-4044/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-4044 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-4044 - OSV: https://osv.dev/vulnerability/CVE-2020-4044 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-4044/ Summaries are generated and may contain mistakes; the official description above is the record.