gh-142533: Prevent CRLF injection in HTTP headers #142605
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Reject CR/LF in header names/values in `http.server` and `wsgiref.headers` to prevent CRLF injection attacks.
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lgtm |
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The pull request involves a fix for CRLF injection vulnerability in
http.serverandwsgirefmodules which allows attackers to inject arbitrary HTTP headers or perform HTTP response splitting attacks by including CR (\r) and LF (\n) characters in header values.This fix adds CRLF validation to
send_header()method inhttp.server, and to three header-manipulation methods in used bywsgiref:__setitem__(),setdefault(), andadd_header().For exception wording, to ensure consistency across both modules, the same
name/valueagnostic wording pattern as already used in existingwsgirefexception messages was used across the change:cpython/Lib/wsgiref/headers.py
Line 45 in b1c9582
Added tests to verify CR/LF rejection in header names and values across http.server and email.message modules, covering all CRLF variants (\r, \n, \r\n).