CVE-2026-33396 CRITICAL

CVE-2026-33396: OneUptime has sandbox escape in Synthetic Monitor Playwright runtime allows project members to execute arbitrary commands on Probe

Vendor Oneuptime
Product oneuptime
Weakness CWE-78
Published March 26, 2026
Last update March 26, 2026

CVSS base score

10.0/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 26, 2026 CVE published
March 26, 2026 Record updated