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Fencer Vulns
high 7.5

CVE-2020-4044 json

Local users can perform a buffer overflow attack against the xrdp-sesman service and then impersonate it

published 2020-06-30 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-25303

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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.

Patch / fix

  • neutrinolabs xrdp 0.9.13.1
  • xrdp Debian 14, Debian 13, Debian 12 0.9.12-1.1

debian advisories DEBIAN-CVE-2020-4044

  • xrdp Ubuntu 20.04 LTS 0.9.12-1ubuntu0.1
  • xrdp Ubuntu Pro 14.04 LTS 0.6.0-1ubuntu0.1+esm2
  • xrdp Ubuntu Pro 16.04 LTS 0.6.1-2ubuntu0.3+esm2
  • xrdp Ubuntu Pro 18.04 LTS 0.9.5-2ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2020-4044

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xrdp SLE Module for Basesystem 15 SP2 0.9.13.1-4.3.1
  • xrdp SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES 12 SP4-LTSS +8 more 0.9.0~git.1456906198.f422461-21.27.1
  • xrdp SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +1 more 0.9.0~git.1456906198.f422461-16.20.1
  • xrdp SLES for SAP 15, SLES 15-LTSS, SLE Module for Basesystem 15 SP1 +2 more 0.9.6-4.8.1
  • xrdp SLES for SAP 12 SP5, SLES 12 SP5 0.9.10-3.3.1

suse advisories SUSE-SU-2020:2142-1SUSE-SU-2020:1991-1SUSE-SU-2020:1943-1SUSE-SU-2020:1933-1SUSE-SU-2020:1918-1

  • xrdp openSUSE Tumbleweed 0.9.15-2.2
  • xrdp openSUSE Leap 15.2 0.9.13.1-lp152.3.3.1
  • xrdp openSUSE Leap 15.1 0.9.6-lp151.4.6.1

opensuse advisories openSUSE-SU-2024:11526-1openSUSE-SU-2020:1200-1openSUSE-SU-2020:0999-1

  • xrdp Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 0.9.13.1-r0

alpine advisories ALPINE-CVE-2020-4044

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-4044 updated cvss 7.5

xrdp: buffer overflow via malicious payloads

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.33% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • neutrinolabs xrdp

Classification

Weakness
  • CWE-121 Stack-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.