CVE-2025-3857: amazon amazon ion dotnet Deserialization of Untrusted Data

Vulnerability summary

CVE-2025-3857 is a high (CVSS 8.7) Deserialization of Untrusted Data vulnerability in amazon amazon ion dotnet. EPSS estimates a 0.61% chance of exploitation in the next 30 days, higher than 48.2% of scored vulnerabilities.

Timeline

1. 21-04-2025
   PublishedVulnerability first disclosed.
2. 14-10-2025
   Last modifiedVulnerability information updated.

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.

• CWE-502Deserialization of Untrusted DataThe product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
• CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.