diff --git a/crates/markdown/src/parser.rs b/crates/markdown/src/parser.rs
index ed9f64374bce262e89565fd42290388f290a0749..1c9376c6d41f26bc350585c8164c549c5404a8e1 100644
--- a/crates/markdown/src/parser.rs
+++ b/crates/markdown/src/parser.rs
@@ -509,6 +509,9 @@ pub(crate) fn extract_code_block_content_range(text: &str) -> Range<usize> {
     if !range.is_empty() && text.ends_with("```") {
         range.end -= 3;
     }
+    if range.start > range.end {
+        range.end = range.start;
+    }
     range
 }
 
@@ -663,6 +666,10 @@ mod tests {
 
         let input = "```python\nprint('hello')\nprint('world')\n```";
         assert_eq!(extract_code_block_content_range(input), 10..40);
+
+        // Malformed input
+        let input = "`````";
+        assert_eq!(extract_code_block_content_range(input), 3..3);
     }
 
     #[test]