diff --git a/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/metadata.rs b/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/metadata.rs
index d47353d180..f4e5a23f6c 100644
--- a/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/metadata.rs
+++ b/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/metadata.rs
@@ -19,6 +19,9 @@ pub(in crate::context_bootstrap) const STORAGE_INTERFACE_NAMES: &[&str] = &[
 ];
 
 pub(in crate::context_bootstrap) const WORKER_SHARED_INTERFACE_NAMES: &[&str] = &[
+    "MediaSourceHandle",
+    "SourceBuffer",
+    "SourceBufferList",
     "EventTarget",
     "Event",
     "CustomEvent",
@@ -118,6 +121,8 @@ const WINDOW_DEDICATED_AND_SHARED_WORKER_INTERFACE_NAMES: &[&str] = &[
     "XMLHttpRequest",
 ];
 const DEDICATED_AND_SHARED_WORKER_INTERFACE_NAMES: &[&str] = &["FileReaderSync"];
+const WINDOW_AND_DEDICATED_WORKER_INTERFACE_NAMES: &[&str] =
+    &["MediaSourceHandle", "SourceBuffer", "SourceBufferList"];
 
 pub(in crate::context_bootstrap) const INDEXED_DB_INTERFACE_NAMES: &[&str] = &[
     "DOMStringList",
@@ -233,6 +238,7 @@ impl ExposureSet {
     const SERVICE_WORKER: u8 = 1 << 3;
 
     const WINDOW_ONLY: Self = Self(Self::WINDOW);
+    const WINDOW_AND_DEDICATED_WORKER: Self = Self(Self::WINDOW | Self::DEDICATED_WORKER);
     const ALL_REALMS: Self =
         Self(Self::WINDOW | Self::DEDICATED_WORKER | Self::SHARED_WORKER | Self::SERVICE_WORKER);
     const WORKERS: Self = Self(Self::DEDICATED_WORKER | Self::SHARED_WORKER | Self::SERVICE_WORKER);
@@ -394,6 +400,9 @@ fn exposure_for_name(name: &str) -> ExposureSet {
         _ if WINDOW_DEDICATED_AND_SHARED_WORKER_INTERFACE_NAMES.contains(&name) => {
             ExposureSet::WINDOW_DEDICATED_AND_SHARED_WORKER
         }
+        _ if WINDOW_AND_DEDICATED_WORKER_INTERFACE_NAMES.contains(&name) => {
+            ExposureSet::WINDOW_AND_DEDICATED_WORKER
+        }
         _ if DEDICATED_AND_SHARED_WORKER_INTERFACE_NAMES.contains(&name) => {
             ExposureSet::DEDICATED_AND_SHARED_WORKER
         }
diff --git a/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/tests.rs b/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/tests.rs
index ec057407af..f088b84371 100644
--- a/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/tests.rs
+++ b/moli-renderer-v8/src/context_bootstrap/exposed_interfaces/tests.rs
@@ -386,3 +386,40 @@ fn worker_realm_lazy_properties_follow_chromium_exposure_sets() {
         vec![false, false, false, false, false, true, false, false]
     );
 }
+
+#[test]
+fn source_buffer_interfaces_are_exposed_only_to_window_and_dedicated_workers() {
+    crate::ensure_v8_for_test();
+    for (realm, expected) in [
+        (super::RealmKind::DedicatedWorker, true),
+        (super::RealmKind::SharedWorker, false),
+        (super::RealmKind::ServiceWorker, false),
+    ] {
+        let mut isolate = v8::Isolate::new(Default::default());
+        let scope = pin!(v8::HandleScope::new(&mut isolate));
+        let scope = &mut scope.init();
+        let context = v8::Context::new(scope, Default::default());
+        let scope = &mut v8::ContextScope::new(scope, context);
+        let global = context.global(scope);
+        crate::context_bootstrap::install_worker_lazy_exposed_interfaces(
+            scope, global, realm, true,
+        )
+        .expect("worker interfaces");
+        for name in ["MediaSourceHandle", "SourceBuffer", "SourceBufferList"] {
+            assert_eq!(
+                global.has_own_property(scope, v8str(scope, name).into()),
+                Some(expected),
+                "{realm:?}/{name}"
+            );
+            if expected {
+                assert!(
+                    global
+                        .get(scope, v8str(scope, name).into())
+                        .unwrap()
+                        .is_function(),
+                    "{name} materialization"
+                );
+            }
+        }
+    }
+}
diff --git a/moli-renderer-v8/src/context_bootstrap/specs/registry.rs b/moli-renderer-v8/src/context_bootstrap/specs/registry.rs
index 0f3304f01b..0703c98e37 100644
--- a/moli-renderer-v8/src/context_bootstrap/specs/registry.rs
+++ b/moli-renderer-v8/src/context_bootstrap/specs/registry.rs
@@ -4,6 +4,18 @@ use crate::web_api_interfaces;
 use std::collections::HashSet;
 
 const CONSTRUCTOR_SPECS_BEFORE_STREAMS: &[ConstructorSpec] = &[
+    ConstructorSpec {
+        interface: web_api_interfaces::MediaSourceHandle::DESCRIPTOR,
+        kind: ConstructorKind::Illegal,
+    },
+    ConstructorSpec {
+        interface: web_api_interfaces::SourceBuffer::DESCRIPTOR,
+        kind: ConstructorKind::Illegal,
+    },
+    ConstructorSpec {
+        interface: web_api_interfaces::SourceBufferList::DESCRIPTOR,
+        kind: ConstructorKind::Illegal,
+    },
     ConstructorSpec {
         interface: web_api_interfaces::External::DESCRIPTOR,
         kind: ConstructorKind::Illegal,
diff --git a/moli-renderer-v8/src/script_vm/tests/media_source_buffer_interface_exposure_interfaces.rs b/moli-renderer-v8/src/script_vm/tests/media_source_buffer_interface_exposure_interfaces.rs
new file mode 100644
index 0000000000..ac32111d26
--- /dev/null
+++ b/moli-renderer-v8/src/script_vm/tests/media_source_buffer_interface_exposure_interfaces.rs
@@ -0,0 +1,39 @@
+use super::*;
+
+#[test]
+fn media_source_buffer_interface_exposure_interfaces_have_realm_local_constructors_and_exposure() {
+    for url in [
+        "https://interface-exposure.test/",
+        "http://interface-exposure.test/",
+    ] {
+        let mut vm = new_storage_test_vm(url);
+        assert_eq!(vm.eval(r#"
+(() => {
+  const assert = (ok, message) => { if (!ok) throw Error(message); };
+  const names = ["MediaSourceHandle", "SourceBuffer", "SourceBufferList"];
+  const parents = {"MediaSourceHandle": null, "SourceBuffer": "EventTarget", "SourceBufferList": "EventTarget"};
+  if (!document.documentElement) document.appendChild(document.createElement('html'));
+  if (!document.body) document.documentElement.appendChild(document.createElement('body'));
+  const child = document.createElement('iframe');
+  document.body.appendChild(child);
+  const other = child.contentWindow;
+  for (const realm of [window, other]) {
+    for (const name of names) {
+      const C = realm[name];
+      assert(typeof C === 'function' && C.name === name && C.length === 0, name + ' constructor');
+      assert(C.prototype.constructor === C, name + ' prototype identity');
+      assert(Object.getPrototypeOf(C.prototype) === (parents[name] ? realm[parents[name]].prototype : realm.Object.prototype), name + ' prototype inheritance');
+      assert(realm[name] === C, name + ' stable lazy materialization');
+      for (const invoke of [() => C(), () => new C(), () => Reflect.construct(C, [], function Subclass() {})]) {
+        let error;
+        try { invoke(); } catch (caught) { error = caught; }
+        assert(error instanceof realm.TypeError, name + ' rejects construction in callee realm');
+      }
+      assert(C !== (realm === window ? other[name] : window[name]), name + ' distinct realm constructors');
+    }
+  }
+  return 'passed';
+})()
+"#).unwrap(), "passed", "{url}");
+    }
+}
diff --git a/moli-renderer-v8/src/script_vm/tests/mod.rs b/moli-renderer-v8/src/script_vm/tests/mod.rs
index 699018b728..e58a055c97 100644
--- a/moli-renderer-v8/src/script_vm/tests/mod.rs
+++ b/moli-renderer-v8/src/script_vm/tests/mod.rs
@@ -2180,3 +2180,5 @@ mod response_blob_mime;
 mod intersection_target_order;
 
 mod media_device_interfaces;
+
+mod media_source_buffer_interface_exposure_interfaces;
diff --git a/moli-renderer-v8/src/web_api_interfaces.rs b/moli-renderer-v8/src/web_api_interfaces.rs
index 7e4bb8f88c..9bad2688bd 100644
--- a/moli-renderer-v8/src/web_api_interfaces.rs
+++ b/moli-renderer-v8/src/web_api_interfaces.rs
@@ -20,6 +20,9 @@ macro_rules! interfaces {
 }
 
 interfaces! {
+    MediaSourceHandle;
+    SourceBuffer: EventTarget;
+    SourceBufferList: EventTarget;
     AbortController;
     AbortSignal: EventTarget;
     AbstractRange;