High severity8.3NVD Advisory· Published Jul 29, 2024· Updated Apr 15, 2026

CVE-2024-41671

Description

Twisted is an event-based framework for internet applications, supporting Python 3.6+. The HTTP 1.0 and 1.1 server provided by twisted.web could process pipelined HTTP requests out-of-order, possibly resulting in information disclosure. This vulnerability is fixed in 24.7.0rc1.

Affected packages

Versions sourced from the GitHub Security Advisory.

Package	Affected versions	Patched versions
twistedPyPI	< 24.7.0rc1	24.7.0rc1

Patches

046a164f89a0

Merge commit from fork

https://github.com/twisted/twistedAdi RoibanJul 29, 2024via ghsa

commit

4 files changed · +41 −2

src/twisted/web/newsfragments/12263.bugfix+1 −0 added

@@ -0,0 +1 @@
+twisted.web.util.redirectTo now HTML-escapes the provided URL in the fallback response body it returns (GHSA-cf56-g6w6-pqq2). The issue is being tracked with CVE-2024-41810.
\ No newline at end of file

src/twisted/web/newsfragments/9839.bugfix+1 −0 added

@@ -0,0 +1 @@
+twisted.web.util.redirectTo now HTML-escapes the provided URL in the fallback response body it returns (GHSA-cf56-g6w6-pqq2, CVE-2024-41810).

src/twisted/web/_template_util.py+1 −1 modified

@@ -92,7 +92,7 @@ def render_GET(self, request):
     </body>
 </html>
 """ % {
-        b"url": URL
+        b"url": escape(URL.decode("utf-8")).encode("utf-8")
     }
     return content

src/twisted/web/test/test_util.py+38 −1 modified

@@ -5,7 +5,6 @@
 Tests for L{twisted.web.util}.
 """
 
-
 import gc
 
 from twisted.internet import defer
@@ -64,6 +63,44 @@ def test_redirectToUnicodeURL(self):
         targetURL = "http://target.example.com/4321"
         self.assertRaises(TypeError, redirectTo, targetURL, request)
 
+    def test_legitimateRedirect(self):
+        """
+        Legitimate URLs are fully interpolated in the `redirectTo` response body without transformation
+        """
+        request = DummyRequest([b""])
+        html = redirectTo(b"https://twisted.org/", request)
+        expected = b"""
+<html>
+    <head>
+        <meta http-equiv=\"refresh\" content=\"0;URL=https://twisted.org/\">
+    </head>
+    <body bgcolor=\"#FFFFFF\" text=\"#000000\">
+    <a href=\"https://twisted.org/\">click here</a>
+    </body>
+</html>
+"""
+        self.assertEqual(html, expected)
+
+    def test_maliciousRedirect(self):
+        """
+        Malicious URLs are HTML-escaped before interpolating them in the `redirectTo` response body
+        """
+        request = DummyRequest([b""])
+        html = redirectTo(
+            b'https://twisted.org/"><script>alert(document.location)</script>', request
+        )
+        expected = b"""
+<html>
+    <head>
+        <meta http-equiv=\"refresh\" content=\"0;URL=https://twisted.org/&quot;&gt;&lt;script&gt;alert(document.location)&lt;/script&gt;\">
+    </head>
+    <body bgcolor=\"#FFFFFF\" text=\"#000000\">
+    <a href=\"https://twisted.org/&quot;&gt;&lt;script&gt;alert(document.location)&lt;/script&gt;\">click here</a>
+    </body>
+</html>
+"""
+        self.assertEqual(html, expected)
+
 
 class ParentRedirectTests(SynchronousTestCase):
     """

4a930de12fb6

Merge commit from fork

https://github.com/twisted/twistedAdi RoibanJul 29, 2024via ghsa

commit

3 files changed · +127 −21

src/twisted/web/http.py+14 −7 modified

@@ -2082,16 +2082,21 @@ def _dataReceived_TRAILER(self) -> bool:
         @returns: C{False}, as there is either insufficient data to continue,
             or no data remains.
         """
-        if (
-            self._receivedTrailerHeadersSize + len(self._buffer)
-            > self._maxTrailerHeadersSize
-        ):
-            raise _MalformedChunkedDataError("Trailer headers data is too long.")
-
         eolIndex = self._buffer.find(b"\r\n", self._start)
 
         if eolIndex == -1:
             # Still no end of network line marker found.
+            #
+            # Check if we've run up against the trailer size limit: if the next
+            # read contains the terminating CRLF then we'll have this many bytes
+            # of trailers (including the CRLFs).
+            minTrailerSize = (
+                self._receivedTrailerHeadersSize
+                + len(self._buffer)
+                + (1 if self._buffer.endswith(b"\r") else 2)
+            )
+            if minTrailerSize > self._maxTrailerHeadersSize:
+                raise _MalformedChunkedDataError("Trailer headers data is too long.")
             # Continue processing more data.
             return False
 
@@ -2101,6 +2106,8 @@ def _dataReceived_TRAILER(self) -> bool:
             del self._buffer[0 : eolIndex + 2]
             self._start = 0
             self._receivedTrailerHeadersSize += eolIndex + 2
+            if self._receivedTrailerHeadersSize > self._maxTrailerHeadersSize:
+                raise _MalformedChunkedDataError("Trailer headers data is too long.")
             return True
 
         # eolIndex in this part of code is equal to 0
@@ -2421,8 +2428,8 @@ def lineReceived(self, line):
             self.__header = line
 
     def _finishRequestBody(self, data):
-        self.allContentReceived()
         self._dataBuffer.append(data)
+        self.allContentReceived()
 
     def _maybeChooseTransferDecoder(self, header, data):
         """

src/twisted/web/newsfragments/12248.bugfix+1 −0 added

@@ -0,0 +1 @@
+The HTTP 1.0 and 1.1 server provided by twisted.web could process pipelined HTTP requests out-of-order, possibly resulting in information disclosure (CVE-2024-41671/GHSA-c8m8-j448-xjx7)

src/twisted/web/test/test_http.py+112 −14 modified

@@ -136,7 +136,7 @@ def process(self):
         data = self.content.read()
         length = self.getHeader(b"content-length")
         if length is None:
-            length = networkString(str(length))
+            length = str(length).encode()
         request = b"'''\n" + length + b"\n" + data + b"'''\n"
         self.setResponseCode(200)
         self.setHeader(b"Request", self.uri)
@@ -564,17 +564,23 @@ def test_noPipelining(self):
 
 class PipeliningBodyTests(unittest.TestCase, ResponseTestMixin):
     """
-    Tests that multiple pipelined requests with bodies are correctly buffered.
+    Pipelined requests get buffered and executed in the order received,
+    not processed in parallel.
     """
 
     requests = (
         b"POST / HTTP/1.1\r\n"
         b"Content-Length: 10\r\n"
         b"\r\n"
-        b"0123456789POST / HTTP/1.1\r\n"
-        b"Content-Length: 10\r\n"
-        b"\r\n"
         b"0123456789"
+        # Chunk encoded request.
+        b"POST / HTTP/1.1\r\n"
+        b"Transfer-Encoding: chunked\r\n"
+        b"\r\n"
+        b"a\r\n"
+        b"0123456789\r\n"
+        b"0\r\n"
+        b"\r\n"
     )
 
     expectedResponses = [
@@ -591,14 +597,16 @@ class PipeliningBodyTests(unittest.TestCase, ResponseTestMixin):
             b"Request: /",
             b"Command: POST",
             b"Version: HTTP/1.1",
-            b"Content-Length: 21",
-            b"'''\n10\n0123456789'''\n",
+            b"Content-Length: 23",
+            b"'''\nNone\n0123456789'''\n",
         ),
     ]
 
-    def test_noPipelining(self):
+    def test_stepwiseTinyTube(self):
         """
-        Test that pipelined requests get buffered, not processed in parallel.
+        Imitate a slow connection that delivers one byte at a time.
+        The request handler (L{DelayedHTTPHandler}) is puppeted to
+        step through the handling of each request.
         """
         b = StringTransport()
         a = http.HTTPChannel()
@@ -607,10 +615,9 @@ def test_noPipelining(self):
         # one byte at a time, to stress it.
         for byte in iterbytes(self.requests):
             a.dataReceived(byte)
-        value = b.value()
 
         # So far only one request should have been dispatched.
-        self.assertEqual(value, b"")
+        self.assertEqual(b.value(), b"")
         self.assertEqual(1, len(a.requests))
 
         # Now, process each request one at a time.
@@ -619,8 +626,95 @@ def test_noPipelining(self):
             request = a.requests[0].original
             request.delayedProcess()
 
-        value = b.value()
-        self.assertResponseEquals(value, self.expectedResponses)
+        self.assertResponseEquals(b.value(), self.expectedResponses)
+
+    def test_stepwiseDumpTruck(self):
+        """
+        Imitate a fast connection where several pipelined
+        requests arrive in a single read. The request handler
+        (L{DelayedHTTPHandler}) is puppeted to step through the
+        handling of each request.
+        """
+        b = StringTransport()
+        a = http.HTTPChannel()
+        a.requestFactory = DelayedHTTPHandlerProxy
+        a.makeConnection(b)
+
+        a.dataReceived(self.requests)
+
+        # So far only one request should have been dispatched.
+        self.assertEqual(b.value(), b"")
+        self.assertEqual(1, len(a.requests))
+
+        # Now, process each request one at a time.
+        while a.requests:
+            self.assertEqual(1, len(a.requests))
+            request = a.requests[0].original
+            request.delayedProcess()
+
+        self.assertResponseEquals(b.value(), self.expectedResponses)
+
+    def test_immediateTinyTube(self):
+        """
+        Imitate a slow connection that delivers one byte at a time.
+
+        (L{DummyHTTPHandler}) immediately responds, but no more
+        than one
+        """
+        b = StringTransport()
+        a = http.HTTPChannel()
+        a.requestFactory = DummyHTTPHandlerProxy  # "sync"
+        a.makeConnection(b)
+
+        # one byte at a time, to stress it.
+        for byte in iterbytes(self.requests):
+            a.dataReceived(byte)
+            # There is never more than one request dispatched at a time:
+            self.assertLessEqual(len(a.requests), 1)
+
+        self.assertResponseEquals(b.value(), self.expectedResponses)
+
+    def test_immediateDumpTruck(self):
+        """
+        Imitate a fast connection where several pipelined
+        requests arrive in a single read. The request handler
+        (L{DummyHTTPHandler}) immediately responds.
+
+        This doesn't check the at-most-one pending request
+        invariant but exercises otherwise uncovered code paths.
+        See GHSA-c8m8-j448-xjx7.
+        """
+        b = StringTransport()
+        a = http.HTTPChannel()
+        a.requestFactory = DummyHTTPHandlerProxy
+        a.makeConnection(b)
+
+        # All bytes at once to ensure there's stuff to buffer.
+        a.dataReceived(self.requests)
+
+        self.assertResponseEquals(b.value(), self.expectedResponses)
+
+    def test_immediateABiggerTruck(self):
+        """
+        Imitate a fast connection where a so many pipelined
+        requests arrive in a single read that backpressure is indicated.
+        The request handler (L{DummyHTTPHandler}) immediately responds.
+
+        This doesn't check the at-most-one pending request
+        invariant but exercises otherwise uncovered code paths.
+        See GHSA-c8m8-j448-xjx7.
+
+        @see: L{http.HTTPChannel._optimisticEagerReadSize}
+        """
+        b = StringTransport()
+        a = http.HTTPChannel()
+        a.requestFactory = DummyHTTPHandlerProxy
+        a.makeConnection(b)
+
+        overLimitCount = a._optimisticEagerReadSize // len(self.requests) * 10
+        a.dataReceived(self.requests * overLimitCount)
+
+        self.assertResponseEquals(b.value(), self.expectedResponses * overLimitCount)
 
     def test_pipeliningReadLimit(self):
         """
@@ -1523,7 +1617,11 @@ def test_unfinishedTrailerHeader(self):
             lambda b: None,  # pragma: nocov
         )
         p._maxTrailerHeadersSize = 10
-        p.dataReceived(b"3\r\nabc\r\n0\r\n0123456789")
+        # 9 bytes are received so far, in 2 packets.
+        # For now, all is ok.
+        p.dataReceived(b"3\r\nabc\r\n0\r\n01234567")
+        p.dataReceived(b"\r")
+        # Once the 10th byte is received, the processing fails.
         self.assertRaises(
             http._MalformedChunkedDataError,
             p.dataReceived,

Vulnerability mechanics

Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

News mentions

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cvss	0.540
epss	0.000
exploit	0.000
kev	0.000
patch	-0.070
ransomware	0.000