CVE-2026-89049

Server-side request forgery in the Session Manager port forwarding functionality in AWS Systems Manager Agent

CRITICAL
9.9
CVSS Score
Published: September 10, 2026 at 06:34 PM UTC
Updated: September 10, 2026 at 07:58 PM UTC
1 product affected across 1 vendorAmazon SSM Agent

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Severity
CRITICAL9.9
Exploit prediction
EPSS 0.7%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.3.4851.0
Affected range stops below 3.3.4851.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

9.9CRITICALAMZN
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-918CWE-1289

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