diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index d7630fb25d..97c201bb96 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -660,6 +660,7 @@ TEST_CASE(ECMA262_match)
         { "[\\0]"sv, "\0"sv, true, ECMAScriptFlags::BrowserExtended },
         { "[\\0]"sv, "\0"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::BrowserExtended) },
         { "[\\01]"sv, "\1"sv, true, ECMAScriptFlags::BrowserExtended },
+        { "(\0|a)"sv, "a"sv, true }, // #9686, Should allow null bytes in pattern
     };
     // clang-format on
 
diff --git a/Userland/Libraries/LibRegex/RegexLexer.cpp b/Userland/Libraries/LibRegex/RegexLexer.cpp
index 69b2b4d345..671e2cb4fa 100644
--- a/Userland/Libraries/LibRegex/RegexLexer.cpp
+++ b/Userland/Libraries/LibRegex/RegexLexer.cpp
@@ -109,7 +109,7 @@ Token Lexer::next()
         }
     };
 
-    while (m_index <= m_input.length()) {
+    while (m_index < m_input.length()) {
         auto ch = peek();
         if (ch == '(')
             return emit_token(TokenType::LeftParen);
@@ -175,9 +175,6 @@ Token Lexer::next()
             }
         }
 
-        if (ch == '\0')
-            break;
-
         return emit_token(TokenType::Char);
     }