Uptime Kuma Stored XSS via Matomo Analytics Site ID on Public Status Pages
18Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.1
exploitation probability
—
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
Affected products
louislam · uptime-kuma