CVE-2026-89049

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

State: Published
Severity: 8.5 High
Published: Sep 10, 2026
Updated: Sep 10, 2026
Reserved: Sep 10, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	8.5 High	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	AMZN
3.1	9.9 Critical	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H	AMZN

Weaknesses

CWE-918 Server-Side request forgery (SSRF)
CWE-1289 Improper validation of unsafe equivalence in input

Affected Products

Product	Versions
Amazon SSM AgentAWS	before 3.3.4851.0Affected

References

https://github.com/aws/amazon-ssm-agent/releases/tag/3.3.4851.0patch
https://aws.amazon.com/security/security-bulletins/2026-107-aws/vendor-advisory
https://github.com/aws/amazon-ssm-agent/security/advisories/GHSA-w9jw-h72g-6hxcthird-party-advisory

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