diff --git a/osc/core.py b/osc/core.py
index 00ed806c..5ac4a6af 100644
--- a/osc/core.py
+++ b/osc/core.py
@@ -2796,7 +2796,9 @@ def binary(data: bytes):
 
     We're using heuristics according to OBS: src/backend/BSSrcServer/filediff - look for "diff binary detection"
     """
-    binary_chars = re.findall(b"[\x00-\0x07\x0e-\x1f]", data)
+    if b"\0" in data:
+        return True
+    binary_chars = re.findall(b"[\x00-\x07\x0e-\x1f]", data)
     return len(binary_chars) * 40 > len(data)
 
 
diff --git a/tests/test_core.py b/tests/test_core.py
index 1303645c..9009d967 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -159,12 +159,12 @@ class TestBinaryFile(unittest.TestCase):
         path = os.path.join(self.tmpdir, "binary")
         with open(path, "wb") as f:
             f.write(1000 * b"a")
-            f.write(b"\0")
+            f.write(b"\1")
         self.assertFalse(binary_file(path))
 
         with open(path, "wb") as f:
             f.write(4096 * b"a")
-            f.write(b"\0")
+            f.write(b"\1")
         self.assertFalse(binary_file(path))
 
     def test_binary(self):
@@ -173,19 +173,26 @@ class TestBinaryFile(unittest.TestCase):
         # sufficient control chars in first 4k
         with open(path, "wb") as f:
             f.write(1000 * b"a")
-            f.write(26 * b"\0")
+            f.write(26 * b"\1")
         self.assertTrue(binary_file(path))
 
         # sufficient control chars in first 4k
         with open(path, "wb") as f:
             f.write(3993 * b"a")
-            f.write(103 * b"\0")
+            f.write(103 * b"\1")
+        self.assertTrue(binary_file(path))
+
+        # a single \0 is good enough for us to say it's a binary file
+        with open(path, "wb") as f:
+            f.write(3993 * b"a")
+            f.write(b"\0")
+            f.write(999 * b"\1")
         self.assertTrue(binary_file(path))
 
         # detected as text because we're reading only first 4k characters
         with open(path, "wb") as f:
             f.write(4096 * b"a")
-            f.write(1000 * b"\0")
+            f.write(1000 * b"\1")
         self.assertFalse(binary_file(path))