# Amazon.IonDotnet is vulnerable to Denial of Service attacks

Advisory record · `GHSA-q5r6-9qwq-g2wj`

- **Identifiers:** `GHSA-q5r6-9qwq-g2wj` · `CVE-2025-11573`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html) · [CWE-1286](https://cwe.mitre.org/data/definitions/1286.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md) · [CWE-1286](https://agentprime.io/advisories/tag/cwe-1286.md)
- **Published:** 9 Oct 2025
- **Updated:** 9 Oct 2025
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 9 Oct 2025, 22:15 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `Amazon.IonDotnet` (NuGet): affected `<1.3.2`; fixed in `1.3.2`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.7 High, CVSS 4.0: `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`, from CNA (AMZN)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0043, the 37th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:22 UTC: First seen by agentprime
- 31 Oct 2026, 15:22 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-q5r6-9qwq-g2wj)

## Sources

- [GitHub Advisory Database: GHSA-q5r6-9qwq-g2wj](https://github.com/advisories/GHSA-q5r6-9qwq-g2wj)
- [OSV: GHSA-q5r6-9qwq-g2wj](https://osv.dev/vulnerability/GHSA-q5r6-9qwq-g2wj)
- <https://github.com/amazon-ion/ion-dotnet/security/advisories/GHSA-q5r6-9qwq-g2wj>
- <https://nvd.nist.gov/vuln/detail/CVE-2025-11573>
- <https://github.com/amazon-ion/ion-dotnet/pull/160>
- <https://github.com/amazon-ion/ion-dotnet/commit/edaff75fe5abbb71e647bed812c608c0c5e2fbab>
- <https://aws.amazon.com/security/security-bulletins/AWS-2025-022>
- <https://github.com/amazon-ion/ion-dotnet>
- <https://github.com/amazon-ion/ion-dotnet/releases/tag/v1.3.2>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-q5r6-9qwq-g2wj>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-q5r6-9qwq-g2wj/>. Everything for agents: <https://agentprime.io/llms.txt>.