Issues in Loom for AWS

Bulletin ID: 2026-124-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 10/02/2026 12:00 PM PDT Description: Loom is an AWS Labs open-source AI agent orchestration platform. We have identified and addressed three issues in Loom for AWS, described below. We recommend upgrading to the latest version (1.7.0) and ensuring any forked or derivative code is patched to incorporate the new fixes. - CVE-2026-103956 ‐ Authentication bypass in Loom for AWS (CWE-306, CWE-1188) An issue in the authentication dependency in Loom for AWS versions <1.6.1 allowed any network client to obtain full administrative authority over the agent control plane ‐ including registering tool servers, reading stored integration credentials, and rewriting IAM role policies attached to managed agent roles ‐ via any request to the application API in a deployment where no identity provider was configured. This issue was addressed in version 1.6.1, released 2026-08-04. - CVE-2026-103957 ‐ OAuth2 token and credential disclosure via outbound request handling in Loom for AWS (CWE-918, CWE-201) An issue in the OAuth2 discovery handling in Loom for AWS versions <1.7.0 allowed an authenticated user with the mcp:write or a2a:write scope to configure a well-known discovery URL whose document directed the backend to send OAuth2 client secrets or another user's access token to a third-party-controlled endpoint. The 1.6.1 release blocked internal-address reach for this code path but did not fully address the token disclosure. This issue was fully addressed in version 1.7.0. - CVE-2026-103958 ‐ Outbound request handling issue in tool server and remote agent connections in Loom for AWS (CWE-918) An issue in the tool server (MCP) and remote agent (A2A) connection handling in Loom for AWS versions <1.7.0 allowed an authenticated user with the mcp:write or a2a:write scope to direct connection requests to arbitrary internal network locations — including the container's credential-vending endpoint ‐ and read the responses. This issue was addressed in version 1.7.0. Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Severity from

NVD

Also known as

CVE-2026-103957, CVE-2026-103958

• aws.amazon.com/security/security-bulletins/rss/2026-124-aws/
• www.cve.org/CVERecord?id=CVE-2026-103956
• www.cve.org/CVERecord?id=CVE-2026-103957
• www.cve.org/CVERecord?id=CVE-2026-103958