Improper handling of highly compressed data in ion-java - CVE-2026-85786
Published: November 9, 2026
Vulnerability identifier: #VU162747
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-85786
CWE-ID: CWE-409
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to cause a memory-amplification denial of service in applications using Amazon ion-java.
The vulnerability exists due to improper handling of highly compressed input by the GZIP auto-decompression handler, including an ineffective opt-out when processing crafted compressed Ion documents. An unauthenticated remote attacker can submit a document that expands to an arbitrarily large size during decompression and exhausts available memory.
Affected software
ion-java
How to mitigate CVE-2026-85786
Install security update from vendor's website.
ion-java - update to 1.12.1