diff --git a/js/layers/fires.js b/js/layers/fires.js
index 01062b0..ebc1ea2 100644
--- a/js/layers/fires.js
+++ b/js/layers/fires.js
@@ -59,7 +59,7 @@ export default function create(ctx) {
       if (!loc) continue;
       const title = ev.title || 'Wildfire';
       const category = (ev.categories && ev.categories[0] && ev.categories[0].title) || 'Wildfires';
-      const link = ev.link || (ev.id ? `https://eonet.gsfc.nasa.gov/api/v3/events/${ev.id}` : null);
+      const link = lib.safeUrl(ev.link || (ev.id ? `https://eonet.gsfc.nasa.gov/api/v3/events/${encodeURIComponent(ev.id)}` : ''));
       const dateTxt = loc.date ? new Date(loc.date).toISOString().replace('T', ' ').replace('.000Z', ' UTC') : '—';
 
       ds.entities.add({
@@ -88,11 +88,11 @@ export default function create(ctx) {
         },
         description:
           `<table class="cesium-infoBox-defaultTable"><tbody>` +
-          `<tr><th>Event</th><td>${title}</td></tr>` +
-          `<tr><th>Category</th><td>${category}</td></tr>` +
+          `<tr><th>Event</th><td>${lib.escapeHtml(title)}</td></tr>` +
+          `<tr><th>Category</th><td>${lib.escapeHtml(category)}</td></tr>` +
           `<tr><th>Last report</th><td>${dateTxt}</td></tr>` +
           `</tbody></table>` +
-          (link ? `<p><a href="${link}" target="_blank" rel="noopener">Open event on EONET ↗</a></p>` : '') +
+          (link ? `<p><a href="${lib.escapeHtml(link)}" target="_blank" rel="noopener">Open event on EONET ↗</a></p>` : '') +
           `<p style="opacity:.7">Active wildfire event from NASA EONET (real data).</p>`,
       });
       count++;
diff --git a/js/layers/quakes.js b/js/layers/quakes.js
index 02f30d1..d8c252a 100644
--- a/js/layers/quakes.js
+++ b/js/layers/quakes.js
@@ -64,7 +64,8 @@ export default function create(ctx) {
     const depth = coords[2];
     const mag = p.mag;
     const timeMs = p.time;
-    const place = p.place || 'Unknown location';
+    const place = p.place || 'Unknown location'; // raw: used in name/label (text contexts)
+    const url = lib.safeUrl(p.url);
     const size = baseSize(mag);
     const color = magColor(mag);
     const recentAtBuild = typeof timeMs === 'number' && (Date.now() - timeMs) < 3_600_000;
@@ -93,11 +94,11 @@ export default function create(ctx) {
       description:
         `<table class="cesium-infoBox-defaultTable"><tbody>` +
         `<tr><th>Magnitude</th><td>M${mag.toFixed(1)}</td></tr>` +
-        `<tr><th>Place</th><td>${place}</td></tr>` +
+        `<tr><th>Place</th><td>${lib.escapeHtml(place)}</td></tr>` +
         `<tr><th>Depth</th><td>${depth != null ? depth.toFixed(1) + ' km' : '—'}</td></tr>` +
         `<tr><th>Time (UTC)</th><td>${timeMs != null ? new Date(timeMs).toISOString().replace('T', ' ').replace('.000Z', ' UTC') : '—'}</td></tr>` +
         `</tbody></table>` +
-        (p.url ? `<p><a href="${p.url}" target="_blank" rel="noopener">USGS event page ↗</a></p>` : ''),
+        (url ? `<p><a href="${lib.escapeHtml(url)}" target="_blank" rel="noopener">USGS event page ↗</a></p>` : ''),
     });
 
     // Labels only for the notable quakes, to keep the globe legible.
diff --git a/js/lib.js b/js/lib.js
index 8d6b939..8179c78 100644
--- a/js/lib.js
+++ b/js/lib.js
@@ -77,6 +77,24 @@ export function altitudeColor(CONFIG, altMeters) {
   return c.aircraftHigh;
 }
 
+// Escape a string for safe interpolation into InfoBox description HTML.
+// Feeds like USGS/EONET are trusted, but this is defense-in-depth for the
+// public deploy (and the InfoBox is a real HTML sink).
+export function escapeHtml(s) {
+  return String(s == null ? '' : s)
+    .replace(/&/g, '&amp;')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#39;');
+}
+
+// Only allow http(s) URLs into href attributes (blocks javascript:/data: URLs).
+export function safeUrl(u) {
+  const s = String(u == null ? '' : u).trim();
+  return /^https?:\/\//i.test(s) ? s : '';
+}
+
 // CSS hex → Cesium.Color, optional alpha.
 export function cz(hex, alpha) {
   const col = Cesium.Color.fromCssColorString(hex);