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Important Algif_aead Privilege Escalation Vulnerability in Ubuntu 20.04

Linuxsecurity •LinuxSecurity Advisories • April 30, 2026

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS - Ubuntu 14.04 LTS Summary: kmod has been updated to block loading of the algif_aead kernel module. Software Description: - kmod: tools for managing Linux kernel modules Details: USN-8226-1 added a mitigation to kmod to disable loading the algif_aead module. This update adds the same mitigation to Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. Original advisory details: It was discovered that the Linux kernel algif_aead module contained a logic flaw allowing a local attacker to escalate privileges to root. This update to the kmod package disables loading the algif_aead module as a measure to mitigate the issue until kernel updates are made available. See the following URL for more information

The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 LTS kmod 27-1ubuntu2.1+esm1 Available with Ubuntu Pro Ubuntu 18.04 LTS kmod 24-1ubuntu3.5+esm1 Available with Ubuntu Pro Ubuntu 16.04 LTS kmod 22-1ubuntu5.2+esm1 Available with Ubuntu Pro Ubuntu 14.04 LTS kmod 15-0ubuntu7+esm1 Available with Ubuntu Pro After a standard system update you need to reboot your computer to make all the necessary changes.

CVE-2026-31431

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Privilege Escalation Vulnerability in Ubuntu's Algif_aead Module A significant privilege escalation vulnerability has been identified in the Linux kernel's algif_aead module, affecting multiple Ubuntu releases including 20.04 LTS, 18.04 LTS, 16.04 LTS, 14.04 LTS, and newer versions up to 25.10. The flaw allows local attackers to escalate privileges to root, posing a serious security risk. In response, the kmod package has been updated to block the loading of the algif_aead module as a temporary mitigation until a permanent kernel fix is deployed. Users are advised to update their systems to specific kmod package versions to mitigate the risk. The CVE associated with this vulnerability is CVE-2026-31431, which was published on April 22, 2026, with a proof of concept released on April 30, 2026. Affected users should reboot their systems after applying the updates to ensure the changes take effect. 4 sources 71

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Important Algif_aead Privilege Escalation Vulnerability in Ubuntu 20.04

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