# CVE-2026-89049: Server-side request forgery in the Session Manager port forwarding functionality in AWS Systems Manager Agent

> Authenticated users can bypass denylists via SSRF to steal IAM credentials from managed instances, requiring an upgrade to the SSM Agent.

- **Severity:** High 8.5 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-w9jw-h72g-6hxc

## What is CVE-2026-89049?

CVE-2026-89049 is a high-severity server-side request forgery vulnerability in AWS Amazon SSM Agent, published on 10 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A server-side request forgery issue due to improper validation of equivalent address representations in the port forwarding to remote hosts functionality in Amazon AWS Systems Manager Agent (SSM Agent) before 3.3.4851.0 on all platforms might allow an authenticated remote user to bypass the remote destination denylist and reach link-local endpoints, potentially obtaining the temporary IAM role credentials of a managed instance and acting with that role's permissions from outside the instance, via a crafted destination host value that uses an alternate representation of a denied link-local address.

To remediate this issue, users should upgrade to version 3.3.4851.0 or later.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-1289 (Improper Validation of Unsafe Equivalence in Input)

## Which versions are affected by CVE-2026-89049?


## How do I fix CVE-2026-89049?

No fix has been published for CVE-2026-89049 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-89049 being exploited?

There is no known exploitation of CVE-2026-89049 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89049 and fix it if it is affected.

What it is: CVE-2026-89049 is a high-severity server-side request forgery vulnerability in AWS Amazon SSM Agent, published on 10 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89049 in the wild and no public exploit code.

Affected product: AWS Amazon SSM Agent. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89049/ (Markdown: https://insights.sbomify.com/CVE-2026-89049/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89049
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89049
- OSV: https://osv.dev/vulnerability/CVE-2026-89049

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89049/
Summaries are generated and may contain mistakes; the official description above is the record.