What’s Vulnerable › Vulnerabilities

CVE-2025-3857: Infinite loop condition in Amazon.IonDotnet

• 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: 2025-04-21 · updated 2026-06-17
• Weakness: CWE-502

Description

When reading binary Ion data through Amazon.IonDotnet using the RawBinaryReader class, Amazon.IonDotnet does not check the number of bytes read from the underlying stream while deserializing the binary format. If the Ion data is malformed or truncated, this triggers an infinite loop condition that could potentially result in a denial of service. Users should upgrade to Amazon.IonDotnet version 1.3.1 and ensure any forked or derivative code is patched to incorporate the new fixes.

Affected products

• Amazon Ion Dotnet: before 1.3.1 — fixed in 1.3.1

How to fix

Upgrade to a fixed version: Amazon Ion Dotnet 1.3.1. Check the vendor advisory for mitigations.

References

• https://aws.amazon.com/security/security-bulletins/AWS-2025-009/
• https://github.com/amazon-ion/ion-dotnet/releases/tag/v1.3.1
• https://github.com/amazon-ion/ion-dotnet/security/advisories/GHSA-gm2p-wf5c-w3pj

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