CVE-2026-107207: LMCache through 0.5.5 Missing Authentication in Frontend Node Catalog Allows SSRF Allowlist Bypass
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.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Deployments with the LMCache frontend monitoring service reachable by an attacker are exposed, because the affected proxy-registration endpoint can be used without authentication. The issue applies to LMCache through version 0.5.5.
What does an attacker need to exploit it?
An attacker needs network access to the frontend monitoring service. They can submit arbitrary host entries to POST /api/proxies and then access those entries through /proxy or /proxy2.
What can an attacker do after bypassing the allowlist?
They can use the frontend service to reach internal hosts and read their responses. The description also indicates they may tamper with nodes or stop the heartbeat.
What can be done if upgrading is not immediately possible?
Restrict attacker access to the frontend monitoring service and, in particular, prevent untrusted clients from reaching POST /api/proxies, /proxy, and /proxy2. This reduces the ability to register arbitrary hosts and use the proxy endpoints to access internal systems.
How can I check for attempted exploitation?
Review requests to POST /api/proxies for unexpected host registrations, then correlate them with requests to /proxy or /proxy2. Investigate proxy activity targeting internal hosts, unexpected node changes, or heartbeat interruptions.