CVE-2026-122193
OS command injection in the example SSM document provisioning script in Trusted Remote Execution (REX) before 2026-07-28 might allow an authenticated remote user who is permitted to invoke the Rex-RO or Rex-RW SSM document to execute arbitrary commands as root on the managed instance, bypassing Cedar policy enforcement. To remediate this issue, users should delete any Rex-RO and Rex-RW SSM documents created from the example script, in each account and Region where it was run.
Am I affected?
Sign in and add the software you use to your watchlist: we check it against every new vulnerability.
Show me how to fix itTimeline
- Published by NVD
- First covered by RedTeamDaily
- Last updated by NVD
Coverage
AWS warns of CVE-2026-122193, a command injection flaw in REX setup guide examples
AWS has published bulletin 2026-173-AWS for CVE-2026-122193, an OS command injection issue in the example script in the Trusted Remote Execution (REX) setup guide. The script creates AWS Systems Manager (SSM) documents Rex-RO and Rex-RW, and poor handling of input parameters let a user with permission to invoke those documents run commands on managed instances outside the REX sandbox. The scriptArgs parameter is affected by the same class of issue, but AWS states this is not an issue in any shipped REX artifact version.
Sources: NVD and CISA known exploited vulnerabilities catalogue.