diff --git a/packages/bundler-plugin-core/src/debug-id-upload.ts b/packages/bundler-plugin-core/src/debug-id-upload.ts
index d201b3a0..3c458388 100644
--- a/packages/bundler-plugin-core/src/debug-id-upload.ts
+++ b/packages/bundler-plugin-core/src/debug-id-upload.ts
@@ -213,7 +213,7 @@ export async function prepareBundleForDebugIdUpload(
   logger: Logger,
   rewriteSourcesHook: RewriteSourcesHook
 ) {
-  let bundleContent;
+  let bundleContent: string;
   try {
     bundleContent = await promisify(fs.readFile)(bundleFilePath, "utf8");
   } catch (e) {
@@ -232,14 +232,11 @@ export async function prepareBundleForDebugIdUpload(
     return;
   }
 
-  const uniqueUploadName = `${debugId}-${chunkIndex}`;
-
+  const uniqueSourceFileUploadPath = getUniqueUploadPath(uploadFolder, chunkIndex, bundleFilePath);
   bundleContent += `\n//# debugId=${debugId}`;
-  const writeSourceFilePromise = fs.promises.writeFile(
-    path.join(uploadFolder, `${uniqueUploadName}.js`),
-    bundleContent,
-    "utf-8"
-  );
+  const writeSourceFilePromise = fs.promises
+    .mkdir(path.dirname(uniqueSourceFileUploadPath), { recursive: true })
+    .then(() => fs.promises.writeFile(uniqueSourceFileUploadPath, bundleContent, "utf-8"));
 
   const writeSourceMapFilePromise = determineSourceMapPathFromBundle(
     bundleFilePath,
@@ -249,7 +246,7 @@ export async function prepareBundleForDebugIdUpload(
     if (sourceMapPath) {
       await prepareSourceMapForDebugIdUpload(
         sourceMapPath,
-        path.join(uploadFolder, `${uniqueUploadName}.js.map`),
+        getUniqueUploadPath(uploadFolder, chunkIndex, sourceMapPath),
         debugId,
         rewriteSourcesHook,
         logger
@@ -261,6 +258,27 @@ export async function prepareBundleForDebugIdUpload(
   await writeSourceMapFilePromise;
 }
 
+function getUniqueUploadPath(uploadFolder: string, chunkIndex: number, filePath: string) {
+  return path.join(
+    uploadFolder,
+    // We add a "chunk index" segment to the path that is a simple incrementing number to avoid name collisions.
+    // Name collisions can happen when files are located "outside" of the current working directory, at different levels but they share a subpath.
+    // Example:
+    // - CWD: /root/foo/cwd
+    // - File 1: /root/foo/index.js -> ../foo/index.js -> foo/index.js
+    // - File 2: /foo/index.js -> ../../foo/index.js -> foo/index.js
+    `${chunkIndex}`,
+    path.normalize(
+      path
+        .relative(process.cwd(), filePath)
+        .split(path.sep)
+        // We filter out these "navigation" segments because a) they look ugly b) they will cause us to break out of the upload folder.
+        .filter((segment) => segment !== ".." && segment !== ".")
+        .join(path.sep)
+    )
+  );
+}
+
 /**
  * Looks for a particular string pattern (`sdbid-[debug ID]`) in the bundle
  * source and extracts the bundle's debug ID from it.
@@ -379,7 +397,8 @@ async function prepareSourceMapForDebugIdUpload(
   }
 
   try {
-    await util.promisify(fs.writeFile)(targetPath, JSON.stringify(map), {
+    await fs.promises.mkdir(path.dirname(targetPath), { recursive: true });
+    await fs.promises.writeFile(targetPath, JSON.stringify(map), {
       encoding: "utf8",
     });
   } catch (e) {