What’s Vulnerable › Vulnerabilities

CVE-2026-103957: Server-side request forgery in the OAuth2 discovery handling in Loom for AWS

• Severity: medium (CVSS 6.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-02 · updated 2026-10-06
• Weakness: CWE-201

Description

Server-side request forgery in the OAuth2 discovery handling in Loom for AWS before 1.7.0 might allow an authenticated remote user to obtain the access token of another user of the deployment and to cause the application to issue requests to arbitrary internal network locations, via a crafted discovery document address supplied when registering a tool server or remote agent configured for delegated authentication. To remediate this issue, users should upgrade to version 1.7.0 or later.

Affected products

• AWS loom: before 1.7.0 — fixed in 1.7.0

How to fix

Upgrade to a fixed version: AWS loom 1.7.0. Check the vendor advisory for mitigations.

References

• https://aws.amazon.com/security/security-bulletins/2026-124-aws/
• https://github.com/awslabs/loom/releases/tag/v1.7.0
• https://github.com/awslabs/loom/security/advisories/GHSA-jcxf-gpf4-58hm

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