diff --git a/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.cpp b/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.cpp
index 54acba5ff4..b27c0978b2 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.cpp
@@ -11,9 +11,9 @@
 
 namespace Web::CSS {
 
-CSSSupportsRule* CSSSupportsRule::create(JS::Realm& realm, NonnullRefPtr<Supports>&& supports, CSSRuleList& rules)
+WebIDL::ExceptionOr<JS::NonnullGCPtr<CSSSupportsRule>> CSSSupportsRule::create(JS::Realm& realm, NonnullRefPtr<Supports>&& supports, CSSRuleList& rules)
 {
-    return realm.heap().allocate<CSSSupportsRule>(realm, realm, move(supports), rules).release_allocated_value_but_fixme_should_propagate_errors();
+    return MUST_OR_THROW_OOM(realm.heap().allocate<CSSSupportsRule>(realm, realm, move(supports), rules));
 }
 
 CSSSupportsRule::CSSSupportsRule(JS::Realm& realm, NonnullRefPtr<Supports>&& supports, CSSRuleList& rules)
diff --git a/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.h b/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.h
index 0c03187869..a28e41a20f 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.h
+++ b/Userland/Libraries/LibWeb/CSS/CSSSupportsRule.h
@@ -20,7 +20,7 @@ class CSSSupportsRule final : public CSSConditionRule {
     WEB_PLATFORM_OBJECT(CSSSupportsRule, CSSConditionRule);
 
 public:
-    static CSSSupportsRule* create(JS::Realm&, NonnullRefPtr<Supports>&&, CSSRuleList&);
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<CSSSupportsRule>> create(JS::Realm&, NonnullRefPtr<Supports>&&, CSSRuleList&);
 
     virtual ~CSSSupportsRule() = default;
 
diff --git a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
index 63b5a51f25..b3456d9ffb 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -3084,7 +3084,7 @@ CSSRule* Parser::convert_to_rule(NonnullRefPtr<Rule> rule)
             }
 
             auto rule_list = CSSRuleList::create(m_context.realm(), child_rules).release_value_but_fixme_should_propagate_errors();
-            return CSSSupportsRule::create(m_context.realm(), supports.release_nonnull(), rule_list);
+            return CSSSupportsRule::create(m_context.realm(), supports.release_nonnull(), rule_list).release_value_but_fixme_should_propagate_errors();
         }
 
         // FIXME: More at rules!