Red Hat Security Advisory: python-idna security update
🔗 CVE IDs covered (1)
📋 Description
CVE-2026-45409 — python-idna: idna: Denial of Service via specially crafted long inputs
🎯 Affected products3
- Red Hat Enterprise Linux BaseOS (v. 8)
- python-idna-0:2.5-8.el8_10.src as a component of Red Hat Enterprise Linux BaseOS (v. 8)
- python3-idna-0:2.5-8.el8_10.noarch as a component of Red Hat Enterprise Linux BaseOS (v. 8)
✅ Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: To mitigate this denial-of-service vulnerability, applications utilizing the `idna` Python library should implement input validation to ensure that domain names do not exceed the standard 253-character length limit before being passed to the `idna.encode()` function. This operational control prevents the processing of excessively long inputs that could lead to resource exhaustion and service unavailability. Applications that pass user-controlled data directly to `idna.encode()` without validation checks (e.g.: DNS length < 254 chars) are affected.