CVE-2026-79659 in Ech0
Summary
by MITRE • 08/25/2026
Ech0 before 4.7.3 contains a server-side request forgery vulnerability in the fetchPeerConnectInfo function that uses unvalidated HTTP requests instead of safe request methods with URL validation. Authenticated attackers can supply arbitrary URLs to access internal services and cloud metadata endpoints by triggering connection health checks or peer connection operations.
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Analysis
by VulDB Data Team • 08/25/2026
The Ech0 software, prior to version 4.7.3, contains a critical server-side request forgery vulnerability within the fetchPeerConnectInfo function. This flaw stems from an implementation error where the application processes HTTP requests without adequate validation of the target URLs provided by users or external peers. Instead of employing safe request methods that restrict communication to predefined internal endpoints or validating URL structures against a whitelist, the system directly utilizes unvalidated inputs for network operations. This architectural weakness allows authenticated attackers to manipulate the destination addresses used during peer connection health checks and other connectivity-related functions. By supplying arbitrary URLs as part of these requests, an attacker can force the vulnerable server to initiate connections to destinations chosen by the adversary rather than intended peers or internal services.
The operational impact of this vulnerability is significant because it enables access to sensitive internal resources that are typically not exposed to external networks. Attackers can leverage this flaw to probe and interact with cloud metadata endpoints, such as those found in AWS EC2 instances (e.g., 169.254.169.254) or similar services on other platforms like Azure and Google Cloud Platform. These metadata endpoints often contain critical authentication credentials, security tokens, and configuration details that can be used to escalate privileges within the cloud environment. Furthermore, the ability to access arbitrary internal services allows attackers to map out the internal network topology, identify additional vulnerable systems, and potentially pivot further into the organization's infrastructure. Since the vulnerability requires authentication, it poses a severe risk in environments where compromised user credentials or insider threats are concerns.
From a classification perspective, this issue aligns with CWE-918, which describes Server-Side Request Forgery (SSRF). The specific mechanism involves the server making requests on behalf of the client to arbitrary URLs without proper validation, falling under the broader category of improper input validation that leads to unintended information disclosure or unauthorized access. In terms of adversary tactics, this vulnerability facilitates reconnaissance and credential theft as outlined in the MITRE ATT&CK framework. Specifically, it supports techniques related to Cloud Infrastructure Discovery (T1580) for accessing metadata endpoints and potentially Credential Access (T1528) if cloud credentials are retrieved from those endpoints. The exploitation of health checks or peer connections also relates to lateral movement strategies where an attacker uses compromised systems as proxies to reach other parts of the network that would otherwise be inaccessible.
Mitigation efforts should prioritize immediate upgrading to Ech0 version 4.7.3 or later, which addresses this flaw by implementing robust URL validation and restricting request methods to safe operations with whitelisted destinations. In cases where an upgrade is not immediately feasible, organizations can implement compensating controls such as deploying a web application firewall that inspects outbound traffic for suspicious patterns targeting internal IP ranges or cloud metadata service IPs. Additionally, network segmentation strategies should be reviewed to ensure that even if SSRF occurs, the blast radius is limited by restricting egress traffic from application servers to only necessary external endpoints and isolated internal services. Regular security audits of peer connection logic are also recommended to prevent similar implementation errors in future updates.