RCE in Hackerbay Oneuptime

CVE-2026-33396

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.

Vulnerability class: Command Injection (OS Command Injection)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.011 (65.6th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 65.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-33396: held from 0.008 to 0.011.

EPSS over last 30 days · oldest: 0.008 · newest: 0.011 · change: +0.003

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-33396?
CVE-2026-33396 is a critical-severity vulnerability in Hackerbay Oneuptime, classified under OS Command Injection. CVSS score: 9.9/10. Published 2026-03-26.
How severe is CVE-2026-33396?
Critical severity. CVSS v3 base score is 9.9 out of 10.