Improper handling of highly compressed data in the GZIP auto-decompression handler in Amazon ion-java before 1.12.0 might allow remote actors to cause a denial of service via a crafted compressed Ion document that expands to an arbitrarily large size upon decompression. To remediate this issue, users should upgrade to version 1.12.0 and configure withGzipDecompressionEnabled(false) and/or set an explicit withMaximumBufferSize() when parsing untrusted input.
https://aws.amazon.com/security/security-bulletins/2026-083-aws/
https://github.com/amazon-ion/ion-java/security/advisories/GHSA-wj53-jv76-65mc
Published: 2026-08-18
Updated: 2026-08-20
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
Severity: High
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: High
Base Score: 8.7
Vector: 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
Severity: High
EPSS: 0.00441