CVE-2026-71285
HIGHCVE-2026-71285 is a high-severity (CVSS 8.1) Cross-site Scripting (XSS) vulnerability. O3 Security confirms whether CVE-2026-71285 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Uptime Kuma's Matomo analytics integration (server/analytics/matomo-analytics.js) injects the admin-configurable Matomo `siteId` value as a bare, unquoted JavaScript expression inside…
Description
Uptime Kuma's Matomo analytics integration (server/analytics/matomo-analytics.js) injects the admin-configurable Matomo siteId value as a bare, unquoted JavaScript expression inside a <script> block rendered on every public status page: _paq.push(['setSiteId', ${escapedSiteIdHTMLAttribute}]);. The escaping pipeline used (jsesc with isScriptContext:true, then html-escaper.escape()) does not escape the characters ], ), ;, (, which are sufficient to break out of the array/push expression context. A siteId value such as 1]);alert(document.cookie)//, once saved by an editor/admin, executes arbitrary JavaScript for every unauthenticated visitor of the public /status/<slug> page, enabling session-cookie theft and full page takeover.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-71285 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-71285 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-71285. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-71285 in your dependencies?
O3 detects CVE-2026-71285 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.