CVE-2026-30887: OneUpTime's Unsandboxed Code Execution in Probe Allows Any Project Member to Achieve RCE

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.6%, percentile 47: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 47% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes @oneuptime/common (npm) < 10.0.18, fixed in 10.0.18. Check your lockfile, including transitive dependencies.

What it is

OneUptime is a solution for monitoring and managing online services. Prior to 10.0.18, OneUptime allows project members to run custom Playwright/JavaScript code via Synthetic Monitors to test websites. However, the system executes this untrusted user code inside the insecure Node.js vm module. By leveraging a standard prototype-chain escape (this.constructor.constructor), an attacker can bypass the sandbox, gain access to the underlying Node.js process object, and execute arbitrary system commands (RCE) on the oneuptime-probe container. Furthermore, because the probe holds database/cluster credentials in its environment variables, this directly leads to a complete cluster compromise. This vulnerability is fixed in 10.0.18.

From the GitHub advisory

Summary OneUptime allows project members to run custom Playwright/JavaScript code via Synthetic Monitors to test websites. However, the system executes this untrusted user code inside the insecure Node.js vm module. By leveraging a standard prototype-chain escape (this.constructor.constructor), an attacker can bypass the sandbox, gain access to the underlying Node.js process object, and execute arbitrary system commands (RCE) on the oneuptime-probe container. Furthermore, because the probe holds database/cluster credentials in its environment variables, this directly leads to a complete cluster compromise.

Details The root cause of the vulnerability exists in Common/Server/Utils/VM/VMRunner.ts where user-supplied JavaScript is executed using vm.runInContext():

The Node.js documentation explicitly warns that the vm module is not a security boundary and should never be used to run untrusted code.

When a user creates a Synthetic Monitor, the code inputted into the Playwright script editor is passed directly to this backend function without any AST filtering or secure isolation (e.g., isolated-vm or a dedicated restricted container).

An attacker can use the payload const proc = this.constructor.constructor('return process')(); to step out of the sandbox context and grab the host's native process object. From there, they can require childprocess to execute arbitrary shell commands.

Weakness type: CWE-94.

Product: @oneuptime/common (npm) · Assigned by: GitHub_M · Published: 2026-03-09

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.59% probability of exploitation activity in the next 30 days; percentile 47.

Timeline

• 2026-03-07 — GitHub-reviewed advisory GHSA-h343-gg57-2q67 published (critical)
• 2026-03-09 — CVE record published by GitHub_M
• 2026-03-10 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-h343-gg57-2q67 github.com
2. CVE.org record CVE-2026-30887 cve.org
3. NVD entry CVE-2026-30887 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

Critical npm advisories · Today’s Security Digest