Ubuntu Security Notices USN-8549-1 USN-8549-1: idna vulnerability Publication date 15 July 2026 Overview idna could be made to consume resources if it received specially crafted input. Releases 26.04 LTS 24.04 LTS 22.04 LTS Open side navigation Close side navigation Packages Details Update instructions References Packages python-idna - Python IDNA2008 (RFC 5891) handling Details It was discovered that idna did not properly reject oversized inputs before performing expensive processing. An attacker could possibly use this issue to cause idna to consume significant resources, leading to a denial of service. It was discovered that idna did not properly reject oversized inputs before performing expensive processing. An attacker could possibly use this issue to cause idna to consume significant resources, leading to a denial of service. 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 26.04 LTS resolute python3-idna – 3.11-1ubuntu0.1 24.04 LTS noble python3-idna – 3.6-2ubuntu0.2 22.04 LTS jammy python3-idna – 3.3-1ubuntu0.2 Reduce your security exposure Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines. Get Ubuntu Pro References CVE-2026-45409 CVE-2026-45409