What is the CVSS score of CVE-2026-33396?

CVE-2026-33396 has a CVSS 3.1 base score of 9.9 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.8%.

Which versions of Node.js are affected by CVE-2026-33396?

OneUptime monitoring platform versions before 10.0.35 allow authenticated low-privileged users to execute arbitrary commands on Probe containers and underlying hosts through sandbox escape in…. A patch is available.

How to fix or mitigate CVE-2026-33396?

Within 24 hours: Identify all OneUptime deployments and current version numbers in your environment. Within 7 days: Upgrade all affected OneUptime instances to version 10.0.35 or later per vendor advisory; restrict ProjectMember role permissions pending upgrade as interim control. Within 30 days: conduct forensic audit of Synthetic Monitor script execution logs for unauthorized launchServer() or _browserType property access; verify no persistence mechanisms were installed during exploitation window.

Node.js CVE-2026-33396

EUVD-2026-16189 CRITICAL

OS Command Injection (CWE-78)

2026-03-26 GitHub_M

RCE Node.js Docker Privilege Escalation Code Injection Oneuptime

9.9

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

9.9 CRITICAL

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Updated

Apr 16, 2026 - 05:48 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

Patch available

Apr 16, 2026 - 05:29 EUVD

10.0.35

EUVD ID Assigned

Mar 26, 2026 - 13:45 euvd

EUVD-2026-16189

Analysis Generated

Mar 26, 2026 - 13:45 vuln.today

CVE Published

Mar 26, 2026 - 13:40 nvd

CRITICAL 9.9

DescriptionGitHub Advisory

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.

AnalysisAI

Remote command execution can be achieved by low-privileged authenticated users (ProjectMember role) in OneUptime monitoring platform versions prior to 10.0.35 by exploiting incomplete sandbox restrictions in Synthetic Monitor Playwright script execution. Attackers can traverse the unblocked _browserType and launchServer properties via page.context().browser()._browserType.launchServer() to spawn arbitrary processes on the Probe container or host. A proof-of-concept exploit exists per SSVC framework data, and the vulnerability carries a CVSS score of 9.9 with Critical severity due to scope change and total technical impact.

Technical ContextAI

OneUptime (CPE: cpe:2.3:a:oneuptime:oneuptime:*:*:*:*:*:*:*:*) is an open-source monitoring and observability platform that executes synthetic monitor scripts using Playwright automation framework. The vulnerability stems from improper neutralization of special elements used in OS commands (CWE-78). The VMRunner.runCodeInNodeVM function executes user-supplied code with access to a live Playwright page object, relying on a denylist-based sandbox to restrict dangerous operations. However, the denylist fails to block the _browserType internal property and launchServer method, allowing attackers to escape the sandbox by traversing from the page context through the browser object hierarchy to invoke launchServer, which can spawn arbitrary system processes with the privileges of the Probe container or host.

RemediationAI

Upgrade OneUptime to version 10.0.35 or later, which contains the vendor-released patch addressing the sandbox escape vulnerability (see GitHub security advisory at https://github.com/OneUptime/oneuptime/security/advisories/GHSA-cqpg-phpp-9jjg and patch commit e8e4ee3ff0740eb131045ab3d67453141c46178a). Organizations unable to immediately upgrade should restrict ProjectMember role assignments to only highly trusted users, implement strict network segmentation to isolate Probe containers from sensitive infrastructure, and monitor Probe container process execution for suspicious launchServer invocations or unexpected child processes. Review and audit all existing synthetic monitor scripts for potentially malicious code, and consider temporarily disabling synthetic monitoring features until patching is complete if the risk tolerance permits operational impact.