CVE-2026-33396: Hackerbay Oneuptime

Critical severity, CVSS 9.9. EPSS: 0.8% chance of exploitation in the next 30 days.

OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.35, a low-privileged authenticated user (ProjectMember) can achieve remote command execution on the Probe container/host by abusing Synthetic Monitor Playwright script execution. Synthetic monitor code is executed in VMRunner.runCodeInNodeVM with a live Playwright page object in context. The sandbox relies on a denylist of blocked properties/methods, but it is incomplete. Specifically, _browserType and launchServer are not blocked, so attacker code can traverse `page.context().browser()._browserType.launchServer(...)` and spawn arbitrary processes. Version 10.0.35 contains a patch.

Affected products

• Hackerbay Oneuptime: before 10.0.35 (fixed in 10.0.35)

Published 2026-03-26. Last modified 2026-10-07.