Infinite loop condition in Amazon.IonDotnet

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X · score source

EPSS

• CVE-2025-3857: 0.62% estimated exploitation activity in the next 30 days; percentile 49.87 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Amazon.IonDotnet (ion-dotnet) is a .NET library with an implementation of the Ion data serialization format. 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. 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…

Published by the source

21 Apr 2025, 16:19 UTC

Last modified by the source

14 Oct 2025, 21:59 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gm2p-wf5c-w3pj

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# Patch Next advisory brief: CVE-2025-3857

Advisory: Infinite loop condition in Amazon.IonDotnet
IDs: CVE-2025-3857, GHSA-gm2p-wf5c-w3pj
Record: https://patchnext.com/advisories/cve-2025-3857 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: amazon.iondotnet 1.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet amazon.iondotnet: affected < 1.3.1; fixed in 1.3.1

## Suggested inspection (read-only)
- NuGet amazon.iondotnet: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on amazon.iondotnet.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gm2p-wf5c-w3pj (GitHub-reviewed advisory GHSA-gm2p-wf5c-w3pj lists affected ranges: NuGet amazon.iondotnet >=0 <1.3.1)

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