# CVE-2026-30956: OneUptime has authorization bypass via client‑controlled is-multi-tenant-query header

> Low-privileged users can bypass tenant isolation and authorization checks via forged headers, leading to cross-tenant data exposure and full account takeover.

- **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:** 10 Mar 2026
- **Updated:** 10 Mar 2026
- **Also known as:** GHSA-r5v6-2599-9g3m

## What is CVE-2026-30956?

CVE-2026-30956 is a critical authentication bypass vulnerability in oneuptime, published on 10 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 10.0.21, a low‑privileged user can bypass authorization and tenant isolation in OneUptime v10.0.20 and earlier by sending a forged is-multi-tenant-query header together with a controlled projectid header. Because the server trusts this client-supplied header, internal permission checks in BasePermission are skipped and tenant scoping is disabled. This allows attackers to access project data belonging to other tenants, read sensitive User fields via nested relations, leak plaintext resetPasswordToken, and reset the victim’s password and fully take over the account. This results in cross‑tenant data exposure and full account takeover. This vulnerability is fixed in 10.0.21.

Weakness: CWE-862 (Missing Authorization), CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-30956?

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 | 10.0.21 |
| `@oneuptime/common` | npm | All versions | 10.0.21 |

Products: Hackerbay Oneuptime.

## How do I fix CVE-2026-30956?

Upgrade @oneuptime/common to 10.0.21 or later.

## Is CVE-2026-30956 being exploited?

There is no known exploitation of CVE-2026-30956 in the wild and no public exploit code.

## 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-2026-30957](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)
- [CVE-2026-30921](https://insights.sbomify.com/CVE-2026-30921/): OneUptime Synthetic Monitor RCE via exposed Playwright browser object (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-30956 and fix it if it is affected.

What it is: CVE-2026-30956 is a critical authentication bypass vulnerability in oneuptime, published on 10 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-30956 in the wild and no public exploit code.

Affected packages and fixed versions:
- @oneuptime/common (npm): affected all versions; fixed in 10.0.21
- @oneuptime/common (npm): affected all versions; fixed in 10.0.21

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-2026-30956/ (Markdown: https://insights.sbomify.com/CVE-2026-30956/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-30956
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-30956
- OSV: https://osv.dev/vulnerability/CVE-2026-30956

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-30956/
Summaries are generated and may contain mistakes; the official description above is the record.