diff --git a/Lib/binhex.py b/Lib/binhex.py
index 1c3f3429032..90e59bce733 100644
--- a/Lib/binhex.py
+++ b/Lib/binhex.py
@@ -324,11 +324,11 @@ class _Rledecoderengine:
         mark = len(self.pre_buffer)
         if self.pre_buffer[-3:] == RUNCHAR + b'\0' + RUNCHAR:
             mark = mark - 3
-        elif self.pre_buffer[-1] == RUNCHAR:
+        elif self.pre_buffer[-1:] == RUNCHAR:
             mark = mark - 2
         elif self.pre_buffer[-2:] == RUNCHAR + b'\0':
             mark = mark - 2
-        elif self.pre_buffer[-2] == RUNCHAR:
+        elif self.pre_buffer[-2:-1] == RUNCHAR:
             pass # Decode all
         else:
             mark = mark - 1
diff --git a/Misc/NEWS b/Misc/NEWS
index 0b66254f5e4..125a5f0dfb9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -23,6 +23,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #6369: Fix an RLE decompression bug in the binhex module.
+
 - Issue #6344: Fixed a crash of mmap.read() when passed a negative argument.
 
 Build