CVE-2026-71285

Received Received - Intake

XSS in Uptime Kuma Matomo Analytics Integration

Publication date: 2026-08-05

Last updated on: 2026-08-10

Assigner: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

Description

Uptime Kuma's Matomo analytics integration (server/analytics/matomo-analytics.js) injects the admin-configurable Matomo value as a bare, unquoted JavaScript expression inside a

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-05

Last Modified

2026-08-10

Generated

2026-08-16

AI Q&A

2026-08-05

EPSS Evaluated

2026-08-15

NVD

CVE-2026-71285

EUVD

EUVD-2026-53370

Affected Vendors & Products

Vendor	Product	Version / Range
matomo	matomo	*
louislam	uptime_kuma	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

Uptime Kuma's Matomo analytics integration injects an admin-configurable Matomo siteId value into a JavaScript expression on public status pages without proper escaping. This allows an attacker to craft a siteId that breaks out of the intended context and executes arbitrary JavaScript code for every unauthenticated visitor.

Detection Guidance

Check Uptime Kuma's public status pages for unexpected JavaScript execution or unusual Matomo siteId values in the page source. Inspect the rendered HTML for unquoted or improperly escaped siteId values in the analytics script block.

Impact Analysis

An attacker could steal session cookies or take over the entire page for visitors of public status pages. This requires the attacker to have admin privileges to set the malicious siteId, but once set, all unauthenticated visitors are affected.

Compliance Impact

This vulnerability could lead to unauthorized access to user data, violating GDPR's data protection principles and HIPAA's security requirements for protected health information. It may result in data breaches and non-compliance penalties.

Mitigation Strategies

Update Uptime Kuma to the latest patched version. If an update is unavailable, disable the Matomo analytics integration in the admin panel. Review and sanitize any existing siteId values to remove special characters.

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