---
id: "GHSA-xmrv-pmrh-hhx2"
kind: "vulnerability"
aliases: ["GHSA-xmrv-pmrh-hhx2"]
title: "CVE-2026-89090 - Denial of service in the event stream header decoder in AWS SDK for Go v2"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["aws", "aws-sdk-go-v2", "event-stream", "go", "lab-disclosure", "package"]
not_affected_if: ["no-event-streams", "patched-sdk"]
published_at: null
first_seen_at: "2026-10-24T18:43:45+00:00"
updated_at: "2026-10-25T04:51:45+00:00"
sources: [{"source": "lab", "url": "https://aws.amazon.com/security/security-bulletins/rss/2026-110-aws/", "first_seen_at": "2026-10-24T18:43:45+00:00"}]
---

# CVE-2026-89090 - Denial of service in the event stream header decoder in AWS SDK for Go v2

The EventStream header decoder in AWS SDK for Go v2 does not validate a header value type byte, so a crafted response frame can terminate the process that is reading it. The attacker gets a denial of service, not code execution.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the version of `github.com/aws/aws-sdk-go-v2` in `go.mod` or `go list -m github.com/aws/aws-sdk-go-v2`, and confirm whether the code uses event stream APIs (for example Amazon Transcribe streaming, S3 Select, or Kinesis SubscribeToShard)

## Fix

- Upgrade `github.com/aws/aws-sdk-go-v2` to `2026-03-23` or later, then rebuild and redeploy
- Patch any forked or vendored copy of the SDK's event stream decoder

## Timeline

- 2026-10-24T18:43:45+00:00 lab https://aws.amazon.com/security/security-bulletins/rss/2026-110-aws/ — AWS: CVE-2026-89090 - Denial of service in the event stream header decoder in AWS SDK for Go v2

## Documents

- [advisory] AWS: CVE-2026-89090 - Denial of service in the event stream header decoder in AWS SDK for Go v2 https://aws.amazon.com/security/security-bulletins/rss/2026-110-aws/

## From the sources

CVE-2026-89090 - Denial of service in the event stream header decoder in AWS SDK for Go v2

### CVE-2026-89090 - Denial of service in the event stream header decoder in AWS SDK for Go v2

Bulletin ID: 2026-110-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 09/11/2026 10:00 AM PDT

Description:

An issue exists in the the EventStream header decoder in AWS SDK for Go v2 in versions predating 2026-03-23. An actor can send a malformed EventStream response frame containing a crafted header value type byte outside the valid range, which can cause the host process to terminate.

Impacted versions: < 2026-03-23

Resolution:

This issue has been addressed in versions 2026-03-23 and above. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds:

Not applicable.

References:

- CVE-2026-89090
- GHSA-xmrv-pmrh-hhx2

 Please email aws-security@amazon.com with any security questions or concerns.

---

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