CVE-2026-85786

Improper handling of highly compressed data in Amazon ion-java before 1.12.1 might allow remote attackers to cause a denial of service via a crafted compressed Ion document that expands to an arbitrarily large size upon decompression due to insufficient coverage of the GZIP auto-decompression opt-out introduced for CVE-2026-75936. To remediate this issue, users should upgrade to version 1.12.1.