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Description

daphne before 4.2.2 reconstructs a raw HTTP request from Twisted's parsed headers and feeds it to autobahn for WebSocket handshake processing. Twisted does not treat \x0b, \x0c, \x1c, \x1d, \x1e, or \x85 as header line separators, but autobahn decodes header values to str and calls splitlines(). An attacker can exploit this parser differential to inject additional headers into the ASGI scope passed to the application. daphne now rejects requests with these bytes in any header value with a 400 response.

PUBLISHED Reserved 2026-05-06 | Published 2026-06-03 | Updated 2026-06-03 | Assigner DSF




LOW: 3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Problem types

CWE-444 (Inconsistent Interpretation of HTTP Requests -- "HTTP Request/Response Smuggling")

Product status

Default status
unaffected

4.2.0 (python)
affected

4.2.2 (python)
unaffected

Timeline

2026-04-09:Initial report received.
2026-05-06:Vulnerability confirmed.

Credits

Rene Henningsen reporter

Carlton Gibson remediation developer

References

github.com/django/daphne/blob/main/CHANGELOG.txt release-notes

cve.org (CVE-2026-44546)

nvd.nist.gov (CVE-2026-44546)

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