CVE-2026-0865

medium

Description

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

References

https://mail.python.org/archives/list/[email protected]/thread/BJ6QPHNSHJTS3A7CFV6IBMCAP2DWRVNT/

https://github.com/python/cpython/pull/143917

https://github.com/python/cpython/issues/143916

https://github.com/python/cpython/commit/f7fceed79ca1bceae8dbe5ba5bc8928564da7211

https://github.com/python/cpython/commit/e4846a93ac07a8ae9aa18203af0dd13d6e7a6995

https://github.com/python/cpython/commit/66da7bf6fe7b81e3ecc9c0a25bd47d4616c8d1a6

https://github.com/python/cpython/commit/4802b96a2cde58570c24c13ef3289490980961c5

https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2

https://github.com/python/cpython/commit/23e3c0ae867cca0130e441e776c9955b9027c510

https://github.com/python/cpython/commit/22e4d55285cee52bc4dbe061324e5f30bd4dee58

Details

Source: Mitre, NVD

Published: 2026-01-20

Updated: 2026-02-13

Risk Information

CVSS v2

Base Score: 6.1

Vector: CVSS2#AV:N/AC:L/Au:M/C:N/I:C/A:N

Severity: Medium

CVSS v3

Base Score: 4.5

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

Severity: Medium

CVSS v4

Base Score: 5.9

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

Severity: Medium

EPSS

EPSS: 0.00067