| Name | CVE-2020-27837 |
| Description | A flaw was found in GDM in versions prior to 3.38.2.1. A race condition in the handling of session shutdown makes it possible to bypass the lock screen for a user that has autologin enabled, accessing their session without authentication. This is similar to CVE-2017-12164, but requires more difficult conditions to exploit. |
| 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 |
|---|
| gdm3 (PTS) | jessie, jessie (lts) | 3.14.1-7+deb8u1 | vulnerable |
| stretch (security), stretch (lts), stretch | 3.22.3-3+deb9u3 | vulnerable |
| buster | 3.30.2-3 | vulnerable |
| bullseye | 3.38.2.1-1 | fixed |
| bookworm | 43.0-3 | fixed |
| sid, trixie | 47.0-3 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| gdm3 | source | jessie | (unfixed) | end-of-life | | |
| gdm3 | source | (unstable) | 3.38.2.1-1 | | | |
Notes
[buster] - gdm3 <no-dsa> (Minor issue)
[stretch] - gdm3 <no-dsa> (Minor issue)
https://gitlab.gnome.org/GNOME/gdm/-/issues/660
https://gitlab.gnome.org/GNOME/gdm/-/commit/dcdbaaa04012541ad2813cf83559d91d52f208b9 (master)
https://gitlab.gnome.org/GNOME/gdm/-/commit/9b6d9b24a5f69674447c7bc9aacfab0988b914bd (3.38.2.1)