# CVE-2026-30921: OneUptime Synthetic Monitor RCE via exposed Playwright browser object

> Low-privileged users can execute arbitrary code on the probe host by injecting malicious Playwright scripts into synthetic monitors.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Mar 2026
- **Updated:** 10 Mar 2026
- **Also known as:** GHSA-4j36-39gm-8vq8

## What is CVE-2026-30921?

CVE-2026-30921 is a critical code injection vulnerability in oneuptime, published on 9 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

OneUptime is a solution for monitoring and managing online services. Prior to 10.0.20, OneUptime Synthetic Monitors allow low-privileged project users to submit custom Playwright code that is executed on the oneuptime-probe service. In the current implementation, this untrusted code is run inside Node's vm and is given live host Playwright objects such as browser and page. This creates a distinct server-side RCE primitive: the attacker does not need the classic this.constructor.constructor(...) sandbox escape. Instead, the attacker can directly use the injected Playwright browser object to reach browser.browserType().launch(...) and spawn an arbitrary executable on the probe host/container. This vulnerability is fixed in 10.0.20.

Weakness: CWE-749 (Exposed Dangerous Method or Function)

## Which versions are affected by CVE-2026-30921?

2 open source packages ship an affected version, including @oneuptime/common. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@oneuptime/common` | npm | All versions | 10.0.20 |
| `@oneuptime/common` | npm | All versions | 10.0.20 |

Products: Hackerbay Oneuptime.

## How do I fix CVE-2026-30921?

Upgrade @oneuptime/common to 10.0.20 or later.

## Is CVE-2026-30921 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-30921 exists.

## Other vulnerabilities in oneuptime

- [CVE-2026-33396](https://insights.sbomify.com/CVE-2026-33396/): Code injection in oneuptime (critical 10.0)
- [CVE-2026-32306](https://insights.sbomify.com/CVE-2026-32306/): OneUptime ClickHouse SQL Injection via Aggregate Query Parameters (critical 10.0)
- [CVE-2026-30956](https://insights.sbomify.com/CVE-2026-30956/): OneUptime has authorization bypass via client‑controlled is-multi-tenant-query header (critical 10.0)
- [CVE-2026-30957](https://insights.sbomify.com/CVE-2026-30957/): OneUptime Synthetic Monitor RCE via exposed Playwright browser object (critical 10.0)
- [CVE-2026-30887](https://insights.sbomify.com/CVE-2026-30887/): OneUptime Affected by Unsandboxed Code Execution in Probe Allows Any Project Member to Achieve RCE (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-30921 and fix it if it is affected.

What it is: CVE-2026-30921 is a critical code injection vulnerability in oneuptime, published on 9 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-30921 exists.

Affected packages and fixed versions:
- @oneuptime/common (npm): affected all versions; fixed in 10.0.20
- @oneuptime/common (npm): affected all versions; fixed in 10.0.20

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-30921/ (Markdown: https://insights.sbomify.com/CVE-2026-30921/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-30921
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-30921
- OSV: https://osv.dev/vulnerability/CVE-2026-30921

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-30921/
Summaries are generated and may contain mistakes; the official description above is the record.