diff --git a/content/browser/renderer_host/navigation_request.cc b/content/browser/renderer_host/navigation_request.cc
index 2343aae339b89..778ee66b5a20e 100644
--- a/content/browser/renderer_host/navigation_request.cc
+++ b/content/browser/renderer_host/navigation_request.cc
@@ -10447,12 +10447,15 @@ bool NavigationRequest::IsFencedFrameRequiredPolicyFeatureAllowed(
       network::GetPermissionsPolicyFeatureList(origin);
 
   // Check if the outer document's permissions policies allow all of the
-  // required policies.
-  std::optional<const network::PermissionsPolicy::Allowlist>
-      embedder_allowlist = GetParentFrameOrOuterDocument()
-                               ->GetPermissionsPolicy()
-                               ->GetAllowlistForFeatureIfExists(feature);
-  if (embedder_allowlist && !embedder_allowlist->MatchesAll()) {
+  // required policies. Note: GetAllowlistForFeatureIfExists() must NOT be used
+  // here — it returns nullopt (rather than an empty allowlist) when the
+  // feature is disabled in the embedder via inheritance, which would let a
+  // nested embedder bypass its top-level page's Permissions-Policy opt-out.
+  const network::PermissionsPolicy::Allowlist embedder_allowlist =
+      GetParentFrameOrOuterDocument()
+          ->GetPermissionsPolicy()
+          ->GetAllowlistForFeature(feature);
+  if (!embedder_allowlist.MatchesAll()) {
     return false;
   }