USN-8173-1: polkit vulnerabilities

Publication date

14 April 2026

Overview

Several security issues were fixed in polkit.


Packages

  • policykit-1 - framework for managing administrative policies and privileges

Details

It was discovered that polkit incorrectly handled nested elements in XML
policy files. If an administrator were tricked into installing a malicious
policy file, a remote attacker could possibly use this issue to cause
polkit to crash, resulting in a denial of service. (CVE-2025-7519)

Pavel Kohout discovered that the polkit polkit-agent-helper-1 utility
incorrectly handled long input. A local attacker could possibly use this
issue to cause polkit to crash, resulting in a denial of service.
(CVE-2026-4897)

It was discovered that polkit incorrectly handled nested elements in XML
policy files. If an administrator were tricked into installing a malicious
policy file, a remote attacker could possibly use this issue to cause
polkit to crash, resulting in a denial of service. (CVE-2025-7519)

Pavel Kohout discovered that the polkit polkit-agent-helper-1 utility
incorrectly handled long input. A local attacker could possibly use this
issue to cause polkit to crash, resulting in a denial of service.
(CVE-2026-4897)

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
25.10 questing polkitd –  126-2ubuntu0.1
24.04 LTS noble policykit-1 –  124-2ubuntu1.24.04.3
22.04 LTS jammy policykit-1 –  0.105-33ubuntu0.1

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