CRLF injection in Python - CVE-2026-0672
Published: February 13, 2026
Vulnerability identifier: #VU122814
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:U/U:Green
CVE-ID: CVE-2026-0672
CWE-ID: CWE-93
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Python.org
Affected software:
Python
Python
Detailed vulnerability description
The vulnerability allows a remote attacker to inject arbitrary data in server response.
The vulnerability exists due to insufficient validation of attacker-supplied data when using http.cookies.Morsel. A remote attacker can pass specially crafted data to the application containing CR-LF characters and modify application behavior leading to a spoofing attack.
How to mitigate CVE-2026-0672
Install updates from vendor's website.
Sources
- https://github.com/python/cpython/commit/62700107418eb2cca3fc88da036a243ea975f172
- https://github.com/python/cpython/commit/712452e6f1d4b9f7f8c4c92ebfcaac1705faa440
- https://github.com/python/cpython/commit/7852d72b653fea0199acf5fc2a84f6f8b84eba8d
- https://github.com/python/cpython/commit/918387e4912d12ffc166c8f2a38df92b6ec756ca
- https://github.com/python/cpython/commit/95746b3a13a985787ef53b977129041971ed7f70
- https://github.com/python/cpython/commit/b1869ff648bbee0717221d09e6deff46617f3e85
- https://github.com/python/cpython/issues/143919
- https://github.com/python/cpython/pull/143920
- https://mail.python.org/archives/list/security-announce@python.org/thread/6VFLQQEIX673KXKFUZXCUNE5AZOGZ45M/