Is this vulnerability remotely exploitable over the internet?

Yes. When open registration is enabled (the default), an unauthenticated user can sign up, gain the lowest role (ProjectMember), create a custom JavaScript monitor, and immediately execute arbitrary code through the backend probe.

What level of access does an attacker need to exploit this issue?

The attacker only needs the ability to create or modify custom JavaScript monitors. In typical deployments, this is available to low-privilege project members and can often be reached by any new registrant if self-service registration is not restricted.

What is the safest general fix pattern?

The safest approach is to eliminate execution of untrusted, arbitrary JavaScript in privileged components. If extensibility is required, run user code in a separate, heavily sandboxed environment with minimal permissions, or replace arbitrary scripting with constrained, declarative configurations or a limited DSL.

Severity:

CRITICAL RISK

(9.9)

Arbitrary Code Execution via Insecure JavaScript Sandbox (CWE-94) in OneUptime Custom Monitors

CVE-2026-27574

Published:

Feb 21, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

Remote Code Execution on the Router

April 6, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Remote Code Execution on Router Firmware

April 6, 2026

Vulnerability Type

Category:

Code Injection / Arbitrary Code Execution

CWE:

CWE-94

Impact:

Remote Code Execution and Full Cluster Compromise

Severity:

CRITICAL RISK

(9.9)

CVSS Version:

3.1

Vulnerability Type

Category:

Code Injection / Arbitrary Code Execution

CWE:

CWE-94

Impact:

Remote Code Execution and Full Cluster Compromise

Severity:

CRITICAL RISK

(9.9)

CVSS Version:

3.1

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355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Arbitrary Code Execution via Insecure JavaScript Sandbox (CWE-94) in OneUptime Custom Monitors

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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