CVE-2026-30957: OneUptime Synthetic Monitor RCE via exposed Playwright browser object

OneUptime is a solution for monitoring and managing online services. Prior to 10.0.21, OneUptime Synthetic Monitors allow a low-privileged authenticated project user to execute arbitrary commands on the oneuptime-probe server/container. The root cause is that untrusted Synthetic Monitor code is executed inside Node's vm while live host-realm Playwright browser and page objects are exposed to it. A malicious user can call Playwright APIs on the injected browser object and cause the probe to spawn an attacker-controlled executable. This is a server-side remote code execution issue. It does not require a separate vm sandbox escape. This vulnerability is fixed in 10.0.21.