CVE-2026-107207 in LMCache
Summary
by MITRE • 10/07/2026
LMCache through 0.5.5 contains a server-side request forgery vulnerability in its frontend monitoring service that allows unauthenticated attackers to bypass the proxy allowlist by registering arbitrary hosts. Attackers can add entries via POST /api/proxies and then use /proxy or /proxy2 to reach internal hosts, read responses, and tamper with nodes or stop the heartbeat.
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Analysis
by VulDB Data Team • 10/07/2026
LMCache versions through 0.5.5 are affected by a critical server-side request forgery vulnerability within its frontend monitoring service architecture. This flaw stems from an insufficient validation mechanism in the proxy configuration endpoint, specifically at the POST /api/proxies interface. The application fails to adequately sanitize or restrict user-supplied input when registering new proxy entries, allowing unauthenticated actors to inject arbitrary hostnames and IP addresses into the system's internal routing table. By exploiting this lack of strict allowlist enforcement during the registration phase, attackers can effectively bypass existing security controls designed to limit outbound requests from the monitoring service to trusted domains only.
The operational impact of this vulnerability is severe due to its potential for lateral movement within a network environment. Once an attacker successfully registers a malicious host via the vulnerable API endpoint, they can utilize the /proxy or /proxy2 endpoints to route HTTP requests through the compromised LMCache instance toward internal infrastructure that would otherwise be inaccessible from external networks. This capability transforms the monitoring service into a powerful proxy tool, enabling attackers to conduct reconnaissance against internal assets, exfiltrate sensitive data by reading responses returned from internal services, and potentially tamper with critical node configurations or disrupt cluster stability by stopping heartbeats required for health checks.
From a classification perspective, this vulnerability aligns closely with CWE-918 Server-Side Request Forgery (SSRF), as it involves the server making requests to unintended destinations based on user input without proper validation. Additionally, the exploitation technique maps directly to MITRE ATT&CK tactic T1557, specifically subtechnique T1557.002 Adversary-in-the-Middle, where the compromised service is used as an intermediary to intercept or manipulate communications between clients and servers within a trusted network boundary. The ability to stop heartbeats also touches upon availability impacts described in CWE-400 Uncontrolled Resource Consumption if it leads to denial of service conditions for cluster nodes.
Mitigation strategies should prioritize immediate patching to the latest stable version of LMCache where this input validation logic has been corrected. In environments where upgrading is not immediately feasible, network-level controls such as strict firewall rules restricting outbound traffic from the monitoring service subnet can provide a compensating control. Furthermore, implementing an API gateway with robust authentication and authorization checks for all internal endpoints would prevent unauthenticated access to configuration APIs like POST /api/proxies. Input validation should be enforced at both the application layer using allowlists of permitted domains or IP ranges and at the infrastructure level by ensuring that proxy services cannot resolve or connect to private RFC 1918 address spaces unless explicitly authorized for specific operational purposes.