---
id: CVE-2026-85786
title: >-
  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…
summary: >-
  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…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-409
published: '2026-09-04'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T14:00:33.017'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85786'
references:
  - url: 'https://aws.amazon.com/security/security-bulletins/2026-100-aws/'
    label: ff89ba41-3aa1-4d27-914a-91399e9639e5
  - url: 'https://github.com/amazon-ion/ion-java/releases/tag/v1.12.1'
    label: ff89ba41-3aa1-4d27-914a-91399e9639e5
tags:
  - nvd
epss: 0.00582
epssPercentile: 0.45466
ingestedAt: '2026-09-08T15:33:26.964Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.