CVE-2025-3857: Infinite loop condition in Amazon.IonDotnet
First published: Mon Apr 21 2025(Updated: )
## Summary [Amazon.IonDotnet (ion-dotnet)](https://github.com/amazon-ion/ion-dotnet) is a .NET library with an implementation of the [Ion data serialization format](https://amazon-ion.github.io/ion-docs/). An issue exists in Amazon.IonDotnet and the RawBinaryReader class where, under certain conditions, an actor could trigger an infinite loop condition. ## Impact 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. **Impacted versions: <=1.3.0** ## Patches This issue has been addressed in Amazon.IonDotnet version [1.3.1](https://github.com/amazon-ion/ion-dotnet/releases/tag/v1.3.1). We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. ## Workarounds There are no workarounds. Upgrade to version 1.3.1. ## References If you have any questions or comments about this advisory, contact AWS/Amazon Security via our [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue. ## Credit We would like to thank Josh Coleman from Symbotic for collaborating on this issue through the coordinated vulnerability disclosure process.
Credit: ff89ba41-3aa1-4d27-914a-91399e9639e5
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Amazon IonDotnet | >1.3.1 | |
| nuget/Amazon.IonDotnet | <1.3.1 | 1.3.1 |
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Reference Links
- https://aws.amazon.com/security/security-bulletins/AWS-2025-009/
- https://github.com/amazon-ion/ion-dotnet/security/advisories/GHSA-gm2p-wf5c-w3pj
- https://github.com/amazon-ion/ion-dotnet/commit/34a4f5215eceac1bb7bf434c4f2310d64d1b703b
- https://nvd.nist.gov/vuln/detail/CVE-2025-3857
- https://aws.amazon.com/security/security-bulletins/AWS-2025-009
- https://github.com/advisories/GHSA-gm2p-wf5c-w3pj (Advisory)
Frequently Asked Questions
What is the severity of CVE-2025-3857?
CVE-2025-3857 is classified as a critical severity vulnerability due to the potential for infinite loops when handling malformed Ion data.
How do I fix CVE-2025-3857?
To fix CVE-2025-3857, update Amazon IonDotnet to a version later than 1.3.1 which addresses the vulnerability.
What software is affected by CVE-2025-3857?
CVE-2025-3857 affects Amazon IonDotnet version 1.3.1 and earlier.
What type of vulnerability is CVE-2025-3857?
CVE-2025-3857 is a deserialization vulnerability due to inadequate checks for the number of bytes read from the stream.
What are the consequences of CVE-2025-3857?
Exploitation of CVE-2025-3857 can lead to an application hanging indefinitely due to an infinite loop during binary data deserialization.
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