========================================================================== Ubuntu Security Notice USN-5292-4 February 24, 2022 snapd regression ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 21.10 - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 ESM - Ubuntu 14.04 ESM Summary: USN-5292-1 introduced a regression in snapd. Software Description: - snapd: Daemon and tooling that enable snap packages Details: USN-5292-1 fixed a vulnerability in snapd. Unfortunately that update introduced a regression that could break the fish shell. This update fixes the problem. We apologize for the inconvenience. Original advisory details: 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) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 21.10: snap-confine 2.54.3+21.10.1ubuntu0.2 snapd 2.54.3+21.10.1ubuntu0.2 Ubuntu 20.04 LTS: snap-confine 2.54.3+20.04.1ubuntu0.2 snapd 2.54.3+20.04.1ubuntu0.2 Ubuntu 18.04 LTS: snap-confine 2.54.3+18.04.2ubuntu0.2 snapd 2.54.3+18.04.2ubuntu0.2 Ubuntu 16.04 ESM: snap-confine 2.54.3+16.04.0ubuntu0.1~esm4 snapd 2.54.3+16.04.0ubuntu0.1~esm4 Ubuntu 14.04 ESM: snap-confine 2.54.3+14.04.0ubuntu0.1~esm3 snapd 2.54.3+14.04.0ubuntu0.1~esm3 In general, a standard system update will make all the necessary changes. References: https://ubuntu.com/security/notices/USN-5292-4 https://ubuntu.com/security/notices/USN-5292-1 https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1961365, https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1961791 Package Information: https://launchpad.net/ubuntu/+source/snapd/2.54.3+21.10.1ubuntu0.2 https://launchpad.net/ubuntu/+source/snapd/2.54.3+20.04.1ubuntu0.2 https://launchpad.net/ubuntu/+source/snapd/2.54.3+18.04.2ubuntu0.2