AWS Remediates MCP Server run_script Sandbox Validation
Tech GuruQuick Answer
AWS bulletin 2026-149-AWS says CVE-2026-115845 in the managed MCP Server run_script tool was remediated service-side and requires no customer action. Confirm relevant use and identity controls, document the vendor-managed disposition, and retain evidence.
Confirm Scope And Apply The Supported Remediation
What to do now: Identify teams and agents using the managed AWS MCP Server run_script tool, authentication paths, permissions, logging, session boundaries, owners, and governance records. Confirm use of AWS's managed MCP Server and the run_script tool. The issue concerns code execution within the authenticated user's own isolated session; do not describe it as cross-tenant execution or infer impact to unrelated MCP servers. Do not invent a customer patch. AWS states that the managed service was remediated and no customer action is required; maintain normal least-privilege access and script-review controls. Confirm current service availability, review access and script governance where warranted, document the authority's service-side remediation, test representative API orchestration, and retain evidence.
Last verified: 2026-10-24 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | AWS MCP Server managed run_script tool |
|---|---|
| Advisory | 2026-149-AWS |
| CVE | CVE-2026-115845 |
| Authoritative release date | 2026-10-23 19:00:00 UTC |
| Authority revision date | 2026-10-23 19:00:00 UTC |
| Affected versions | The hosted AWS MCP Server run_script Python sandbox before AWS's service-side remediation; the bulletin lists impacted versions as not applicable because it is a managed service. |
| Fixed version | AWS service-side remediation; no customer action is required |
| CVSS base score | Not provided by the authority |
| CVSS severity | Not provided by the authority |
| Exploitation status | AWS does not state that this issue is being maliciously exploited.; no exploitation claim is inferred. |
What Changed
AWS corrected incomplete Python input validation that could let an authenticated remote user execute arbitrary code within that user's own isolated session environment.
What To Validate Now
- Inventory. Identify teams and agents using the managed AWS MCP Server run_script tool, authentication paths, permissions, logging, session boundaries, owners, and governance records.
- Establish applicability. Confirm use of AWS's managed MCP Server and the run_script tool. The issue concerns code execution within the authenticated user's own isolated session; do not describe it as cross-tenant execution or infer impact to unrelated MCP servers.
- Remediate. Do not invent a customer patch. AWS states that the managed service was remediated and no customer action is required; maintain normal least-privilege access and script-review controls.
- Validate. Confirm current service availability, review access and script governance where warranted, document the authority's service-side remediation, test representative API orchestration, and retain evidence.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
The authority provides no CVSS score and does not claim cross-session escape or malicious exploitation. Separate any broader MCP or agent-risk review from this vendor-managed vulnerability disposition.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
