CVE-2020-16125: gdm3 would start gnome-initial-setup if it cannot contact accountservice

Severity: medium (CVSS 6.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-11-10 · updated 2026-06-17
Weakness: CWE-754

Description

gdm3 versions before 3.36.2 or 3.38.2 would start gnome-initial-setup if gdm3 can't contact the accountservice service via dbus in a timely manner; on Ubuntu (and potentially derivatives) this could be be chained with an additional issue that could allow a local user to create a new privileged account.

Affected products

Gnome Display Manager: before 3.36.2; from 3.38.0 before 3.38.2 — fixed in 3.36.2, 3.38.2

How to fix

Upgrade to a fixed version: Gnome Display Manager 3.36.2, 3.38.2. Check the vendor advisory for mitigations.

References

https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1900314
https://gitlab.gnome.org/GNOME/gdm/-/issues/642
https://securitylab.github.com/advisories/GHSL-2020-202-gdm3-LPE-unresponsive-accounts-daemon
https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1900314
https://gitlab.gnome.org/GNOME/gdm/-/issues/642
https://securitylab.github.com/advisories/GHSL-2020-202-gdm3-LPE-unresponsive-accounts-daemon

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