From 77e0eb25755c3952e5892e02c42588e20d84bca7 Mon Sep 17 00:00:00 2001
From: Tony123-tech <tony1225leung@gmail.com>
Date: Wed, 30 Sep 2026 20:40:11 +0800
Subject: [PATCH] gh-158494: zipimport: raise ZipImportError for corrupt
 deflate data

---
 Lib/test/test_zipimport.py                    | 23 +++++++++++++++++++
 Lib/zipimport.py                              |  5 +++-
 ...-09-30-19-30-00.gh-issue-158494.AbCdEf.rst |  2 ++
 3 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2026-09-30-19-30-00.gh-issue-158494.AbCdEf.rst

diff --git a/Lib/test/test_zipimport.py b/Lib/test/test_zipimport.py
index 76cd85709a63af8..0c14d11825bc48a 100644
--- a/Lib/test/test_zipimport.py
+++ b/Lib/test/test_zipimport.py
@@ -1021,6 +1021,29 @@ def assertDataEntry(name):
 class DeflateCompressedZipImportTestCase(UncompressedZipImportTestCase):
     compression = ZIP_DEFLATED
 
+    def testCorruptDeflateDataRaisesZipImportError(self):
+        # gh-158494: a corrupt deflate stream in a .pyc must surface as.
+        # ZipImportError, not zlib.error.
+        files = {TESTMOD + pyc_ext: test_pyc}
+        self.makeZip(files)
+
+        # Corrupt the deflate stream of the .pyc entry in place.
+        with open(TEMP_ZIP, "r+b") as f:
+            data = f.read()
+            idx = data.find((TESTMOD + pyc_ext).encode())
+            lh = data.rfind(b"PK\x03\x04")
+            name_len, extra_len = struct.unpack_from("<HH", data, lh + 26)
+            data_start = lh + 30 + name_len + extra_len
+            f.seek(data_start)
+            f.write(b"\xff" * 8)
+
+        zipimport._zip_directory_cache.clear()
+        sys.path.insert(0, TEMP_ZIP)
+        self.addCleanup(sys.modules.pop, TESTMOD, None)
+        importlib.invalidate_caches()
+
+        with self.assertRaises(zipimport.ZipImportError):
+            importlib.import_module(TESTMOD)
 
 @support.requires_zstd()
 class ZStdCompressedZipImportTestCase(UncompressedZipImportTestCase):
diff --git a/Lib/zipimport.py b/Lib/zipimport.py
index 19279d1c2bea368..1b91f1e792cf613 100644
--- a/Lib/zipimport.py
+++ b/Lib/zipimport.py
@@ -668,7 +668,10 @@ def _get_data(archive, toc_entry):
                 decompress = _get_zlib_decompress_func()
             except Exception:
                 raise ZipImportError("can't decompress data; zlib not available")
-            return decompress(raw_data, -15)
+            try:
+                return decompress(raw_data, -15)
+            except Exception:
+                raise ZipImportError("could not decompress deflate data")
         case 93:  # zstd
             try:
                 return _zstd_decompress(raw_data)
diff --git a/Misc/NEWS.d/next/Library/2026-09-30-19-30-00.gh-issue-158494.AbCdEf.rst b/Misc/NEWS.d/next/Library/2026-09-30-19-30-00.gh-issue-158494.AbCdEf.rst
new file mode 100644
index 000000000000000..acd6112c2b7563a
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-09-30-19-30-00.gh-issue-158494.AbCdEf.rst
@@ -0,0 +1,2 @@
+Fix :mod:`zipimport` to raise :exc:`zipimport.ZipImportError` instead of
+leaking :exc:`zlib.error` when a zip entry's deflate stream is corrupt.