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.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
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.
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.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-89049 being exploited?
There is no known exploitation of CVE-2026-89049 in the wild and no public exploit code.
Sources
Also known as GHSA-w9jw-h72g-6hxc.