CVE-2025-11573 — Amazon.IonDotnet
Fix: amazon-ion/ion-dotnet#160CVE-2025-11573 is a CWE-1286 vulnerability in Amazon.IonDotnet. A fix is available for Amazon.IonDotnet — see the affected versions and patch details below.
Denial of Service issue in Amazon.IonDotnet
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-11573.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
Amazon.IonDotnetReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Amazon.IonDotnet is a library for the Dotnet language that is used to read and write Amazon Ion data. An issue exists where, under certain circumstances, the library could an infinite loop, resulting in denial of service. As of August 20, 2025, this library has been deprecated and will not receive further updates.
Impact
An infinite loop issue in Amazon.IonDotnet library versions <v1.3.2 may allow a threat actor to cause a denial of service through a specially crafted text input. This invalid input triggered an error condition in the parser that was handled improperly, resulting in an infinite loop.
Impacted versions:
<1.3.2
Patches
This issue has been addressed in Amazon.IonDotnet version 1.3.2. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Workarounds
Only accept data from trusted sources, written using a supported Ion library.
References
If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Amazon.IonDotnet | all versions | 1.3.2dotnet add package Amazon.IonDotnet --version 1.3.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Amazon.IonDotnet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Amazon.IonDotnet to 1.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-11573 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-11573 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-11573. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-11573 in your dependencies?
O3 Security finds CVE-2025-11573 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.