diff --git a/src/parse.rs b/src/parse.rs
index 307e0650..2a87948a 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -472,6 +472,10 @@ fn raw_string(input: Cursor) -> Result<Cursor, Reject> {
             _ => return Err(Reject),
         }
     }
+    if n > 255 {
+        // https://github.com/rust-lang/rust/pull/95251
+        return Err(Reject);
+    }
     while let Some((i, ch)) = chars.next() {
         match ch {
             '"' if input.rest[i + 1..].starts_with(&input.rest[..n]) => {
diff --git a/tests/test.rs b/tests/test.rs
index 0033418e..e0af1512 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -137,7 +137,7 @@ fn literal_raw_string() {
     // https://github.com/rust-lang/rust/pull/95251
     raw_string_literal_with_hashes(256)
         .parse::<TokenStream>()
-        .unwrap();
+        .unwrap_err();
 }
 
 #[test]