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Published: 10 February 2021

When generating the systemd service units for the docker snap (and other similar snaps), snapd does not specify Delegate=yes - as a result systemd will move processes from the containers created and managed by these snaps into the cgroup of the main daemon within the snap itself when reloading system units. This may grant additional privileges to a container within the snap that were not originally intended.

From the Ubuntu Security Team

Gilad Reti and Nimrod Stoler discovered that snapd did not correctly specify cgroup delegation when generating systemd service units for various container management snaps. This could allow a local attacker to escalate privileges via access to arbitrary devices of the container host from within a compromised or malicious container.



Cvss 3 Severity Score


Score breakdown


Package Release Status
Launchpad, Ubuntu, Debian
Released (2.48.3+18.04)
Released (2.48.3+20.04)
Released (2.48.3+20.10)
trusty Does not exist

upstream Needs triage

Released (2.48.3)

Severity score breakdown

Parameter Value
Base score 9.3
Attack vector Local
Attack complexity Low
Privileges required None
User interaction None
Scope Changed
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H