CVE-2026-75935: Memory-amplification denial of service via declared-length preallocation in Amazon ion-java

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-18 · updated 2026-10-22
Weakness: CWE-789

Description

Uncontrolled memory allocation in the binary Ion stream cursor in Amazon ion-java before 1.12.0 might allow remote actors to cause a denial of service via a crafted Ion binary document containing a declared-length field that causes excessive heap preallocation. To remediate this issue, users should upgrade to version 1.12.0.

Affected products

Amazon Ion Java: from 1.9.0 before 1.12.0 — fixed in 1.12.0

How to fix

Upgrade to a fixed version: Amazon Ion Java 1.12.0. Check the vendor advisory for mitigations.

References

https://aws.amazon.com/security/security-bulletins/2026-083-aws/
https://github.com/amazon-ion/ion-java/releases/tag/v1.12.0
https://github.com/amazon-ion/ion-java/security/advisories/GHSA-822f-6gg9-whr5

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