AWS Trusted Remote Execution (REX) setup-guide example SSM documents allow OS command injection (CVE-2026-122193) · updates https://pwn.watch/i/aws-rex-example-ssm-command-injection-cve-2026-122193 On Nov 6 2026 AWS published Important bulletin 2026-173-AWS for CVE-2026-122193 (GHSA-95g5-m242-wvhr): an OS command injection issue in an example from the Trusted Remote Execution (REX) set-up documentation. The example script creates AWS Systems Manager documents Rex-RO and Rex-RW for running scripts on managed instances; due to how that example handled input parameters (including scriptArgs), a user permitted to invoke the SSM document could supply crafted input that runs unintended OS commands on the managed instance outside the REX sandbox. This is not a flaw in a shipped REX artifact — only operators who created those SSM documents by following the guide are affected. AWS removed the example from the guide. Mitigation: delete any Rex-RO / Rex-RW SSM documents created from the example in each account and Region where it was run. No workaround other than deleting the documents. en Fri, 06 Nov 2026 00:00:00 GMT AWS Trusted Remote Execution (REX) setup-guide example SSM documents allow OS command injection (CVE-2026-122193): AWS publishes Important bulletin 2026-173-AWS for CVE-2026-122193: OS command injection in REX set-up guide example SSM documents Rex-RO/Rex-RW; example removed from guide; delete created documents. https://pwn.watch/i/aws-rex-example-ssm-command-injection-cve-2026-122193 https://pwn.watch/i/aws-rex-example-ssm-command-injection-cve-2026-122193#2026-11-06-e7dc2a0c Fri, 06 Nov 2026 00:00:00 GMT high <p><a href="https://aws.amazon.com/security/security-bulletins/2026-173-aws/">Source</a></p>