Fix GH#852: a PEM file must have at least 3 lines

Legrandin · Legrandin · commit eac9de8e129b · 2025-03-15T17:38:29.000+01:00
diff --git a/Changelog.rst b/Changelog.rst
@@ -11,6 +11,7 @@ New features
   Resolved issues
 ---------------
 * GH#846: fix infinite loop with RC4 for data larger than 4GB.
+* GH#852: handle correctly invalid PEM files with less than 3 lines.
 
 Other changes
 -------------
diff --git a/lib/Crypto/IO/PEM.py b/lib/Crypto/IO/PEM.py
@@ -137,6 +137,8 @@ def decode(pem_data, passphrase=None):
 
     # Removes spaces and slit on lines
     lines = pem_data.replace(" ", '').split()
+    if len(lines) < 3:
+        raise ValueError("A PEM file must have at least 3 lines")
 
     # Decrypts, if necessary
     if lines[1].startswith('Proc-Type:4,ENCRYPTED'):
