CVE-2026-103958 in Loom
Summary
by MITRE • 10/02/2026
Server-side request forgery in the tool server and remote agent connection handling in Loom for AWS before 1.7.0 might allow an authenticated remote user to obtain the credentials of the application's own container role and to read responses from arbitrary internal network locations, via a crafted connection address supplied when registering, updating or testing a tool server or remote agent.
To remediate this issue, users should upgrade to version 1.7.0 or later.
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Analysis
by VulDB Data Team • 10/02/2026
The vulnerability identified in Loom for AWS prior to version 1.7.0 represents a critical security flaw rooted in the improper validation of user-supplied input during the registration and configuration processes for tool servers and remote agents. This issue manifests as a Server-Side Request Forgery, commonly abbreviated as SSRF, which allows an authenticated attacker to manipulate the application into making HTTP requests to unintended destinations. The core technical failure lies in the handling of connection addresses provided by users when registering, updating, or testing these components. Instead of strictly validating that the supplied address belongs to a permitted external endpoint, the system fails to adequately restrict the protocol and destination scope, thereby enabling the execution of arbitrary network requests on behalf of the application itself.
This lack of input validation has severe operational implications for cloud environments relying on Loom for AWS. Because the vulnerable components operate with elevated privileges associated with their deployment context, they possess access to instance metadata services and internal network resources that are typically isolated from direct external access. By crafting a malicious connection address, an authenticated remote user can force the application server to query the local instance metadata service at addresses such as 169.254.169.254 or similar cloud-specific endpoints. This action facilitates the exfiltration of sensitive credentials associated with the application's own container role, including temporary security tokens and access keys. Furthermore, the attacker can leverage this capability to probe internal network locations, potentially discovering other vulnerable services, reading responses from private APIs, or pivoting further into the infrastructure by mapping out the internal network topology.
From a classification perspective, this vulnerability aligns with CWE-918, which describes Server-Side Request Forgery flaws where web applications retrieve data from a server without validating user-supplied URLs. The exploitation technique also maps to MITRE ATT&CK techniques related to Cloud Infrastructure Discovery and Credential Access, specifically the use of cloud metadata services to gather information about the environment and steal credentials for lateral movement or privilege escalation. The ability to read responses from arbitrary internal locations underscores the risk of data exfiltration and unauthorized access to sensitive backend systems that are not directly exposed to the internet but remain reachable via SSRF vectors.
To mitigate this vulnerability, organizations must prioritize immediate patching by upgrading Loom for AWS to version 1.7.0 or any later release where these input validation controls have been implemented. In addition to software updates, it is advisable to enforce strict network segmentation and restrict outbound traffic from application servers to only necessary external endpoints using firewall rules or security groups. Implementing a deny-list approach that blocks access to known internal IP ranges and cloud metadata service addresses can provide an additional layer of defense against SSRF attacks. Regular auditing of connection configurations and enforcing least-privilege principles for container roles further reduces the potential impact if such vulnerabilities are exploited in other contexts within the infrastructure.