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Fencer Vulns
critical 9.8

CVE-2018-20177 json

rdesktop versions up to and including v1.8.3 contain an Integer Overflow that leads to a Heap-Based Buffer Overflow in the function rdp_in_…

published 2019-03-15 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-12744

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.9%
EPSS 7.9% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

rdesktop versions up to and including v1.8.3 contain an Integer Overflow that leads to a Heap-Based Buffer Overflow in the function rdp_in_unistr() and results in memory corruption and possibly even a remote code execution.

Patch / fix

  • rdesktop Debian 14, Debian 13, Debian 12 1.8.4-1

debian advisories DEBIAN-CVE-2018-20177

  • rdesktop openSUSE Tumbleweed 1.9.0-4.6
  • rdesktop Package Hub 15 SP1, openSUSE Leap 15.1 1.8.6-bp151.2.3.1

opensuse advisories openSUSE-SU-2024:11298-1openSUSE-SU-2019:2135-1

  • rdesktop Alpine 3.24, Alpine 3.23, Alpine 3.22 +12 more 1.8.6-r0

alpine advisories ALPINE-CVE-2018-20177

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

  • rdesktop Arch Linux 1.8.4-1

arch linux advisories AVG-871

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-2018-20177 updated cvss 5.3

rdesktop: Memory corruption in rdp_in_unistr

  • Red Hat Enterprise Linux 5 rdesktop Red Hat Enterprise Linux 6 rdesktop
    affected: no fix planned “Will not fix”

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

7.93% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • research.checkpoint.com https://research.checkpoint.com/reverse-rdp-attack-code-execution-on-rdp-clients/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

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.