diff --git a/src/syncer.js b/src/syncer.js
index 51932e25b..46bdd8883 100644
--- a/src/syncer.js
+++ b/src/syncer.js
@@ -10,6 +10,11 @@ import util from 'node:util';
 
 const { log } = logger('syncer');
 
+// JSON.stringify does not escape U+2028/U+2029 and readline treats them as line terminators
+// https://github.com/tc39/proposal-json-superset
+function jsonLineStringify(obj) {
+    return JSON.stringify(obj).replace(/\u2028/g, '\\u2028').replace(/\u2029/g, '\\u2029');
+}
 
 function readCache(cacheFile) {
     assert.strictEqual(typeof cacheFile, 'string');
@@ -111,7 +116,7 @@ async function sync(dataLayout, cacheFile) {
             if (!entryStat.isDirectory() && !entryStat.isFile()) continue; // ignore non-files and dirs
             if (entryStat.isSymbolicLink()) continue;
 
-            safe.fs.appendFileSync(newCacheFd, JSON.stringify({ path: entryPath, stat: { mtime: entryStat.mtime.getTime(), size: entryStat.size, inode: entryStat.inode, mode: entryStat.mode } }) + '\n');
+            safe.fs.appendFileSync(newCacheFd, jsonLineStringify({ path: entryPath, stat: { mtime: entryStat.mtime.getTime(), size: entryStat.size, inode: entryStat.inode, mode: entryStat.mode } }) + '\n');
 
             if (curCacheIndex !== cache.length && cache[curCacheIndex].path < entryPath) { // files disappeared. first advance cache as needed
                 advanceCache(entryPath);
@@ -185,7 +190,7 @@ async function finalize(integrityMap, cacheFile) {
             cacheEntry.integrity = integrityMap.get(cacheEntry.path); // { size, sha256 }
             if (typeof cacheEntry.integrity === 'undefined') throw new BoxError(BoxError.INTERNAL_ERROR, `No integrity information for ${cacheEntry.path}`);
         }
-        safe.fs.appendFileSync(tempCacheFd, JSON.stringify(cacheEntry) + '\n');
+        safe.fs.appendFileSync(tempCacheFd, jsonLineStringify(cacheEntry) + '\n');
     }
 
     safe.fs.closeSync(tempCacheFd);