What’s Vulnerable › Vulnerabilities
CVE-2026-32308: OneUptime: Stored XSS via Mermaid Diagram Rendering (securityLevel: "loose")
- Severity: high (CVSS 7.6 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-03-13 · updated 2026-10-07
- Weakness: CWE-79
Description
OneUptime is a solution for monitoring and managing online services. Prior to 10.0.23, the Markdown viewer component renders Mermaid diagrams with securityLevel: "loose" and injects the SVG output via innerHTML. This configuration explicitly allows interactive event bindings in Mermaid diagrams, enabling XSS through Mermaid's click directive which can execute arbitrary JavaScript. Any field that renders markdown (incident descriptions, status page announcements, monitor notes) is vulnerable. This vulnerability is fixed in 10.0.23.
Affected products
- oneuptime: before 10.0.23 — fixed in 10.0.23
How to fix
Upgrade to a fixed version: oneuptime 10.0.23. Check the vendor advisory for mitigations.
References
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