Read the docs
TI-2026-86042 Aliases CVE-2026-122193

OS command injection in Trusted Remote Execution example SSM documents

Priority MEDIUM 45CWE-78Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-78.

Summary

The example SSM document provisioning script in AWS Trusted Remote Execution (REX) before 2026-07-28 contains an OS command injection flaw (CWE-78). An authenticated remote user who is permitted to invoke the Rex-RO or Rex-RW SSM document can run arbitrary commands as root on the managed instance. The attack bypasses Cedar policy enforcement.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01626 76th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
AWStrusted-remote-executionN/A—No fix listedCNA
  • trusted-remote-execution VendorAWS Affected N/A Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for trusted-remote-execution. Delete any Rex-RO and Rex-RW SSM documents created from the example script, in each account and Region where it was run.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Timeline

  1. 2026-11-06 Threatist record created from CVE-2026-122193
  2. 2026-11-06 CISA SSVC decision points changed
  3. 2026-11-06 Priority changed: MEDIUM → LOW
  4. 2026-11-08 Priority changed: LOW → MEDIUM

References

Advisory 2

  • TI-2026-23989 crypto: algif_aead - Revert to operating out-of-place KEVCVSS 3.1HIGH 7.8
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2024-18648 Amazon AWS Amplify CLI before 12.10.1 incorrectly configures the role trust policy of IAM… CVSS 3.1CRITICAL 9.8
  • TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
  • TI-2025-03847 Input validation issue in AWS Amplify Studio UI component properties CVSS 4.0CRITICAL 9.0
  • TI-2026-11603 HTTP/2 Stream Parser Confusion Body-Inspection Bypass in Amazon CloudFront with AWS WAF CVSS 4.0HIGH 7.9
See all 383 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences