Bulletin ID: 2026-122-AWSScope: AWSContent Type: Important (requires attention)Publication Date: 10/01/2026 13:30 PM PDTDescription:Amazon Ion Python is an open-source Python implementation of the Amazon Ion data notation. We identified CVE-2026-104020, an issue in the Ion reader in Amazon Ion Python before version 0.15.0 where a crafted, deeply nested Ion value could cause the application to raise an error or crash, resulting in a denial of service.Impacted versions: < 0.15.0Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.