CVE-2026-0865

Severity CVSS v4.0:

MEDIUM

Type:

CWE-74 Injection

Publication date:

20/01/2026

Last modified:

03/03/2026

Description

User-controlled header names and values containing newlines can allow injecting HTTP headers.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 5.90 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): High
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0

5.90

Severity 4.0

MEDIUM

References to Advisories, Solutions, and Tools

https://github.com/python/cpython/commit/22e4d55285cee52bc4dbe061324e5f30bd4dee58
https://github.com/python/cpython/commit/23e3c0ae867cca0130e441e776c9955b9027c510
https://github.com/python/cpython/commit/286e3ac39984fe85a17f4ab39c64d382137aae5f
https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2
https://github.com/python/cpython/commit/4802b96a2cde58570c24c13ef3289490980961c5
https://github.com/python/cpython/commit/66da7bf6fe7b81e3ecc9c0a25bd47d4616c8d1a6
https://github.com/python/cpython/commit/83ecd18779f286d872f68bfce175651e407d9fff
https://github.com/python/cpython/commit/8bb044d29310bb05d15086cdaa8bf64867d61a97
https://github.com/python/cpython/commit/bfba660085767f8c2d582134e9d511a85eda04cf
https://github.com/python/cpython/commit/c592227ffb48679af9845a45dbb0875d975bb219
https://github.com/python/cpython/commit/e4846a93ac07a8ae9aa18203af0dd13d6e7a6995
https://github.com/python/cpython/commit/f7fceed79ca1bceae8dbe5ba5bc8928564da7211
https://github.com/python/cpython/issues/143916
https://github.com/python/cpython/pull/143917
https://mail.python.org/archives/list/security-announce@python.org/thread/BJ6QPHNSHJTS3A7CFV6IBMCAP2DWRVNT/