diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index 55b7a63ab..74994075a 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -1,5 +1,10 @@
 # God's Eye View Current State
 
+Share links and structured views accept only own keys in their style registries.
+Inherited names such as `constructor` and `__proto__` fall back to the existing
+normal/null defaults without interrupting other restored fields. Programmatic
+visual-style calls ignore unknown or non-string values before mutating state.
+
 Shared distance checks use `src/geoDistance.js` with `{ lat, lon }` points and
 the IUGG mean spherical Earth radius, 6371.0088 km. `greatCircleKm` is
 canonical; `greatCircleMeters` is its exact metre conversion. Missing,
diff --git a/src/sharelink.celestial.test.mjs b/src/sharelink.celestial.test.mjs
index e862aba66..13dedd709 100644
--- a/src/sharelink.celestial.test.mjs
+++ b/src/sharelink.celestial.test.mjs
@@ -778,3 +778,20 @@ test('visual input listeners are revoked before asynchronous UI teardown', () =>
   assert.match(VisualSettings.prototype.stop.toString(), /this\._styleParameters\?\.destroy\(\)/);
   assert.match(VisualSettings.prototype.stop.toString(), /this\._visualEffects\.stop\(\)/);
 });
+
+
+test('share restore rejects inherited styles while continuing later fields', () => {
+  for (const style of ['constructor', '__proto__', 'toString', 'hasOwnProperty', 'unknown']) {
+    const restored = makeManager(`#lat=10&lon=20&style=${style}&cr=1`).parseInitialHash();
+    assert.equal(restored.style, 'normal');
+    assert.equal(restored.celestialRing, true);
+  }
+});
+
+test('programmatic invalid styles are ignored before changing visual state', () => {
+  const target = { activeStyle: 'normal' };
+  for (const value of ['constructor', '__proto__', 'toString', 'hasOwnProperty', 'unknown', {}, null, () => {}]) {
+    assert.doesNotThrow(() => VisualSettings.prototype.setStyle.call(target, value));
+    assert.equal(target.activeStyle, 'normal');
+  }
+});
diff --git a/src/sharelink.js b/src/sharelink.js
index 6072fb1bd..7e0e78b35 100644
--- a/src/sharelink.js
+++ b/src/sharelink.js
@@ -175,7 +175,9 @@ export class ShareLinkManager {
       parseOr(params.get('dd'), 50),
       50,
     );
-    const style = URL_TO_STYLE[params.get('style')] || 'normal';
+    const style = Object.hasOwn(URL_TO_STYLE, params.get('style'))
+      ? URL_TO_STYLE[params.get('style')]
+      : 'normal';
     const decodedLayerState = decodeLayerStateParams(params);
     const state = {
       lat,
diff --git a/src/ui/visualSettings.js b/src/ui/visualSettings.js
index 2aab58f10..b80e4452f 100644
--- a/src/ui/visualSettings.js
+++ b/src/ui/visualSettings.js
@@ -1539,6 +1539,11 @@ export class VisualSettings {
       preserveCyberRestore = false,
     } = {},
   ) {
+    if (
+      typeof styleName !== 'string' ||
+      (styleName !== 'normal' && !Object.hasOwn(STYLES, styleName))
+    )
+      return;
     const { setDetectionStyle } = this.services;
     if (!restore) this.shareLinkManager?.claimRestoreLane?.('visual');
     if (this.hud.getVariant() === 'cyber') {
diff --git a/src/view/index.js b/src/view/index.js
index 8ab56d5a4..fc5385aaa 100644
--- a/src/view/index.js
+++ b/src/view/index.js
@@ -370,7 +370,9 @@ export function viewFromParams(params) {
       pitch_deg: number('pitch'),
     },
     layers: state?.enabledLayerIds ?? [],
-    style: STYLES_BY_URL_NAME[params.get('style')] ?? null,
+    style: Object.hasOwn(STYLES_BY_URL_NAME, params.get('style'))
+      ? STYLES_BY_URL_NAME[params.get('style')]
+      : null,
     map: VIEW_MAPS.includes(map) ? map : null,
     follow,
     annotations: annotationsFromParams(params),
diff --git a/src/view/index.test.mjs b/src/view/index.test.mjs
index 818feb1ba..34299c498 100644
--- a/src/view/index.test.mjs
+++ b/src/view/index.test.mjs
@@ -126,3 +126,20 @@ test('annotations travel in the link, keeping only what the app draws', async ()
   // Too long for a link: the view keeps them, the link leaves them out.
   assert.equal(viewToParams(many).has('an'), false);
 });
+
+test('inherited and unknown style keys do not corrupt a restored view', () => {
+  for (const style of [
+    'constructor',
+    '__proto__',
+    'toString',
+    'hasOwnProperty',
+    'unknown',
+  ]) {
+    const view = viewFromParams(
+      new URLSearchParams({ lat: '10', lon: '20', style, map: 'osm' }),
+    );
+    assert.equal(view.style, null);
+    assert.equal(view.map, 'osm');
+    assert.equal(view.camera.lat, 10);
+  }
+});