Fix catastrophic backtracking issue in header parsing regular expression.

The affected pattern is only used from a single non-public function,
which in turn is not actually used anywhere. It's in dead code. No
security issue.

1 files changed, 1 insertions, 1 deletions

diff --git a/bottle.py b/bottle.py
index c52c20d..130c55d 100755
--- a/bottle.py
+++ b/bottle.py
@@ -3017,7 +3017,7 @@ def parse_range_header(header, maxlen=0):
 
 
 #: Header tokenizer used by _parse_http_header()
-_hsplit = re.compile('(?:(?:"((?:[^"\\\\]+|\\\\.)*)")|([^;,=]+))([;,=]?)').findall
+_hsplit = re.compile('(?:(?:"((?:[^"\\\\]|\\\\.)*)")|([^;,=]+))([;,=]?)').findall
 
 def _parse_http_header(h):
     """ Parses a typical multi-valued and parametrised HTTP header (e.g. Accept headers) and returns a list of values