CVE-2026-89049Network attack vector

Credential theft via alternate-address denylist bypass

Published Sep 10, 2026 · Updated Sep 10, 2026

SSRF in AWS Systems Manager Agent before 3.3.4851.0 allows remote authenticated users to reach link-local endpoints through remote-host port forwarding. The remote-host destination denylist compares address forms without first canonicalizing them, so an alternate representation of a blocked link-local address passes validation. The attacker needs permission to start remote-host port-forwarding sessions; reaching the Instance Metadata Service exposes temporary IAM role credentials usable outside the instance.

CVSS severity9.9
Critical
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in AWS Systems Manager Agent before 3.3.4851.0 allows remote authenticated users to reach link-local endpoints through remote-host port forwarding. The remote-host destination denylist compares address forms without first canonicalizing them, so an alternate representation of a blocked link-local address passes validation. The attacker needs permission to start remote-host port-forwarding sessions; reaching the Instance Metadata Service exposes temporary IAM role credentials usable outside the instance.

The record

CVE
CVE-2026-89049
Published
Sep 10, 2026
Updated
Sep 10, 2026
Vendor
Amazon Web Services
Product
AWS Systems Manager Agent (SSM Agent)
Classifications
CWE-1289, CWE-918, T1552.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.3.4851.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Amazon Web Services · AWS Systems Manager Agent (SSM Agent)version=0 <3.3.4851.0

Published CVSS scores

9.9GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1289Improper Validation of Unsafe Equivalence in Input
CWE-918Server-Side Request Forgery (SSRF)
T1552.005Unsecured Credentials: Cloud Instance Metadata API

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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