diff --git a/crates/turbopack-core/src/issue/mod.rs b/crates/turbopack-core/src/issue/mod.rs
index 30e6123eac468..78ac64b7dea67 100644
--- a/crates/turbopack-core/src/issue/mod.rs
+++ b/crates/turbopack-core/src/issue/mod.rs
@@ -431,6 +431,7 @@ pub struct IssueSource {
     range: Option<Vc<SourceRange>>,
 }
 
+/// The end position is the first character after the range
 #[turbo_tasks::value]
 #[derive(Clone, Debug)]
 enum SourceRange {
diff --git a/crates/turbopack-mdx/src/lib.rs b/crates/turbopack-mdx/src/lib.rs
index 37097793621aa..041a47e1e04ca 100644
--- a/crates/turbopack-mdx/src/lib.rs
+++ b/crates/turbopack-mdx/src/lib.rs
@@ -189,20 +189,22 @@ impl MdxTransformedAsset {
             Err(err) => {
                 let loc = Vc::cell(err.place.map(|p| {
                     let (start, end) = match *p {
+                        // markdown's positions are 1-indexed, SourcePos is 0-indexed.
+                        // Both end positions point to the first character after the range
                         markdown::message::Place::Position(p) => (
                             SourcePos {
-                                line: p.start.line,
-                                column: p.start.column,
+                                line: p.start.line - 1,
+                                column: p.start.column - 1,
                             },
                             SourcePos {
-                                line: p.end.line,
-                                column: p.end.column,
+                                line: p.end.line - 1,
+                                column: p.end.column - 1,
                             },
                         ),
                         markdown::message::Place::Point(p) => {
                             let p = SourcePos {
-                                line: p.line,
-                                column: p.column,
+                                line: p.line - 1,
+                                column: p.column - 1,
                             };
                             (p, p)
                         }