CVE-2026-32308

OneUptime: Stored XSS via Mermaid Diagram Rendering (securityLevel: "loose")

HIGH
7.6
CVSS Score
Published: March 12, 2026 at 09:29 PM UTC
Updated: October 7, 2026 at 08:10 AM UTC
2 products affected across 2 vendorsOneuptimeOneUptime

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Severity
HIGH7.6
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 10.0.23
v < 10.0.23
Affected range stops below 10.0.23, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/OneUptime/oneuptime/security/advisories/GHSA-wvh5-6vjm-23qh

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.6HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-79

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