diff --git a/Libraries/LibRegex/RegexParser.cpp b/Libraries/LibRegex/RegexParser.cpp
index 9a0b2e5f641..5a0fc608646 100644
--- a/Libraries/LibRegex/RegexParser.cpp
+++ b/Libraries/LibRegex/RegexParser.cpp
@@ -1627,9 +1627,14 @@ bool ECMA262Parser::parse_atom_escape(ByteCode& stack, size_t& match_length_mini
             set_error(Error::InvalidNameForCaptureGroup);
             return false;
         }
-        match_length_minimum += maybe_capture_group->minimum_length;
+        auto maybe_length = m_parser_state.capture_group_minimum_lengths.get(maybe_capture_group.value());
+        if (!maybe_length.has_value()) {
+            set_error(Error::InvalidNameForCaptureGroup);
+            return false;
+        }
+        match_length_minimum += maybe_length.value();
 
-        stack.insert_bytecode_compare_values({ { CharacterCompareType::Reference, (ByteCodeValueType)maybe_capture_group->group_index } });
+        stack.insert_bytecode_compare_values({ { CharacterCompareType::Reference, (ByteCodeValueType)maybe_capture_group.value() } });
         return true;
     }
 
@@ -2674,6 +2679,8 @@ bool ECMA262Parser::parse_capture_group(ByteCode& stack, size_t& match_length_mi
                 return false;
             }
 
+            m_parser_state.named_capture_groups.set(name, group_index);
+
             ByteCode capture_group_bytecode;
             size_t length = 0;
             enter_capture_group_scope();
@@ -2693,7 +2700,6 @@ bool ECMA262Parser::parse_capture_group(ByteCode& stack, size_t& match_length_mi
             match_length_minimum += length;
 
             m_parser_state.capture_group_minimum_lengths.set(group_index, length);
-            m_parser_state.named_capture_groups.set(name, { group_index, length });
             return true;
         }
 
diff --git a/Libraries/LibRegex/RegexParser.h b/Libraries/LibRegex/RegexParser.h
index f7e5073d0ca..d5634e89246 100644
--- a/Libraries/LibRegex/RegexParser.h
+++ b/Libraries/LibRegex/RegexParser.h
@@ -98,11 +98,6 @@ protected:
 
     size_t tell() const { return m_parser_state.current_token.position(); }
 
-    struct NamedCaptureGroup {
-        size_t group_index { 0 };
-        size_t minimum_length { 0 };
-    };
-
     struct ParserState {
         Lexer& lexer;
         Token current_token;
@@ -114,8 +109,8 @@ protected:
         size_t match_length_minimum { 0 };
         size_t repetition_mark_count { 0 };
         AllOptions regex_options;
-        HashMap<int, size_t> capture_group_minimum_lengths;
-        HashMap<DeprecatedFlyString, NamedCaptureGroup> named_capture_groups;
+        HashMap<size_t, size_t> capture_group_minimum_lengths;
+        HashMap<DeprecatedFlyString, size_t> named_capture_groups;
 
         explicit ParserState(Lexer& lexer)
             : lexer(lexer)
diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index e975ee96c55..0f11865fc64 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -597,6 +597,7 @@ TEST_CASE(ECMA262_parse)
         { "a{9007199254740992,9007199254740992}"sv, regex::Error::InvalidBraceContent },
         { "(?<a>a)(?<a>b)"sv, regex::Error::DuplicateNamedCapture },
         { "(?<a>a)(?<b>b)(?<a>c)"sv, regex::Error::DuplicateNamedCapture },
+        { "(?<a>(?<a>a))"sv, regex::Error::DuplicateNamedCapture },
         { "(?<1a>a)"sv, regex::Error::InvalidNameForCaptureGroup },
         { "(?<\\a>a)"sv, regex::Error::InvalidNameForCaptureGroup },
         { "(?<\ta>a)"sv, regex::Error::InvalidNameForCaptureGroup },