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Fencer Intel
medium 4.3

CVE-2018-20839 json

systemd 242 changes the VT1 mode upon a logout, which allows attackers to read cleartext passwords in certain circumstances, such as watchi…

published 7y ago modified 4mo ago also EUVD-2018-13379

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

systemd 242 changes the VT1 mode upon a logout, which allows attackers to read cleartext passwords in certain circumstances, such as watching a shutdown, or using Ctrl-Alt-F1 and Ctrl-Alt-F2. This occurs because the KDGKBMODE (aka current keyboard mode) check is mishandled.

Patch / fix

  • plymouth Debian 14, Debian 13, Debian 12 0.9.4-1

debian advisories DEBIAN-CVE-2018-20839

Is CVE-2018-20839 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2018-20839 updated cvss 4.3

systemd: mishandling of the current keyboard mode check leading to passwords being disclosed in cleartext to attacker

  • Red Hat Enterprise Linux 8 systemd, systemd-pam, systemd-libs, systemd-udev, systemd-tests, systemd-container, +1 more
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 systemd, libgudev1, systemd-libs, systemd-sysv, systemd-python, systemd-networkd, +2 more Red Hat Enterprise Linux 9 systemd, systemd-pam, systemd-libs, systemd-oomd, systemd-udev, systemd-ukify, +6 more
    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

2.48% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

References

Sources

Fencer Intel 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.