| Name | CVE-2018-20839 |
| Description | 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. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| plymouth (PTS) | bullseye | 0.9.5-3 | fixed |
| bookworm | 22.02.122-3 | fixed |
| sid, trixie | 24.004.60-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| plymouth | source | (unstable) | 0.9.4-1 | low | | |
Notes
[stretch] - plymouth <no-dsa> (Minor issue)
[jessie] - plymouth <no-dsa> (Minor issue)
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1803993
https://github.com/systemd/systemd/commit/9725f1a10f80f5e0ae7d9b60547458622aeb322f
https://github.com/systemd/systemd/pull/12378
The fix for https://bugs.debian.org/929116 introduced a regression, cf.
https://bugs.debian.org/929229 .
Issue was originally fixed for unstable in 241-4 but was reverted in 241-5
https://gitlab.freedesktop.org/xorg/xserver/issues/857
Upstream from systemd claimed originally it's not an issue in systemd, but
might revisit. Furthermore the issue might be fixed in the xorg xserver.
Tentative merge request: https://gitlab.freedesktop.org/xorg/xserver/merge_requests/241
Further analysis on the problem: https://gitlab.freedesktop.org/xorg/xserver/issues/857#note_201402
plymouth fix: https://gitlab.freedesktop.org/plymouth/plymouth/commit/28ee4012c94b4045b97e5a2a66f66b7688b2dff3 (0.9.4)
The plymouth fix does not seem to be enough though, cf.
https://gitlab.freedesktop.org/xorg/xserver/issues/857#note_220255