CVE-2026-32308 | OneUptime: Stored XSS via Mermaid Diagram Rendering (securityLevel: "loose")

Exp

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.

Published: 2026-03-13 Last update: 2026-03-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-32308 is rated Exploit Available (51.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-32308

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-32308

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-19 0.03% 0.05% +0.02%
2 2026-03-13 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-32308

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 4.7 [email protected]

Weakness enumeration for CVE-2026-32308

GitHub Security Advisory for CVE-2026-32308

GHSA-wvh5-6vjm-23qh · Severity: high · Ecosystem: npm — OneUptime: Stored XSS via Mermaid Diagram Rendering (securityLevel: "loose")

Affected software / configurations for CVE-2026-32308

Vendor Product Version Raw CPE
hackerbay oneuptime < 10.0.23 cpe:2.3:a:hackerbay:oneuptime:*:*:*:*:*:*:*:*

References for CVE-2026-32308

cvelogic Threat Intelligence