diff --git a/dom/base/nsGlobalWindowInner.cpp b/dom/base/nsGlobalWindowInner.cpp
index f40fceaaa299..3a093927b22f 100644
--- a/dom/base/nsGlobalWindowInner.cpp
+++ b/dom/base/nsGlobalWindowInner.cpp
@@ -2400,6 +2400,11 @@ void nsGlobalWindowInner::UpdateTopInnerWindow() {
 bool nsGlobalWindowInner::CanShareMemory(const nsID& aAgentClusterId) {
   MOZ_ASSERT(NS_IsMainThread());
 
+  if (StaticPrefs::
+          dom_postMessage_sharedArrayBuffer_bypassCOOP_COEP_insecure_enabled()) {
+    return true;
+  }
+
   if (!StaticPrefs::dom_postMessage_sharedArrayBuffer_withCOOP_COEP()) {
     return false;
   }
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index 7867d4672a43..65887a252ce7 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -4970,6 +4970,11 @@ const nsAString& WorkerPrivate::Id() {
 bool WorkerPrivate::CanShareMemory(const nsID& aAgentClusterId) {
   AssertIsOnWorkerThread();
 
+  if (StaticPrefs::
+          dom_postMessage_sharedArrayBuffer_bypassCOOP_COEP_insecure_enabled()) {
+    return true;
+  }
+
   if (!StaticPrefs::dom_postMessage_sharedArrayBuffer_withCOOP_COEP()) {
     return false;
   }
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
index 9eb848f3f35a..fe244886b764 100644
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -1903,6 +1903,12 @@
   value: false
   mirror: always
 
+# Overridden in all.js on RELEASE_OR_BETA in order to add the locked attribute.
+- name: dom.postMessage.sharedArrayBuffer.bypassCOOP_COEP.insecure.enabled
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
 # Presentation API
 - name: dom.presentation.enabled
   type: bool
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 213e612281d4..d1b12006ad82 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -4935,3 +4935,11 @@ pref("devtools.devices.url", "https://code.cdn.mozilla.net/devices/devices.json"
 
 // Enable Inactive CSS detection; used both by the client and the server.
 pref("devtools.inspector.inactive.css.enabled", true);
+
+#if defined(NIGHTLY_BUILD) || defined(MOZ_DEV_EDITION)
+// Define in StaticPrefList.yaml and override here since StaticPrefList.yaml
+// doesn't provide a way to lock the pref
+pref("dom.postMessage.sharedArrayBuffer.bypassCOOP_COEP.insecure.enabled", false);
+#else
+pref("dom.postMessage.sharedArrayBuffer.bypassCOOP_COEP.insecure.enabled", false, locked);
+#endif