Affected: Canonical Ltd. snapd

snapd 2.54.2 and earlier created ~/snap directories in user home directories without specifying owner-only permissions. This could allow a local attacker to read information that should have been private. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1

Affected: Ubuntu:18.04:LTS: snapd, Ubuntu:20.04:LTS: snapd

James Troup discovered that snap did not properly manage the permissions for the snap directories. A local attacker could possibly use this issue to expose sensitive information. (CVE-2021-3155)

Ian Johnson discovered that snapd did not properly validate content interfaces and layout paths. A local attacker could possibly use this issue to inject arbitrary AppArmor policy rules, resulting in a bypass of intended access restrictions. (CVE-2021-4120)

The Qualys Research Team discovered that snapd did not properly validate the location of the snap-confine binary. A local attacker could possibly use this issue to execute other arbitrary binaries and escalate privileges. (CVE-2021-44730)

The Qualys Research Team discovered that a race condition existed in the snapd snap-confine binary when preparing a private mount namespace for a snap. A local attacker could possibly use this issue to escalate privileges and execute arbitrary code. (CVE-2021-44731)