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

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required High

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required High

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00067.

Exploitation none

Automatable no

Technical Impact partial

Affected Vendors & Products

Vendors Products
Python Subscribe
Cpython Subscribe

No data.

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

Vendors Products
Python Subscribe
Cpython Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/python/cpython/commit/22e4d55285cee52bc4dbe061324e5f30bd4dee58 cve-icon cve-icon
https://github.com/python/cpython/commit/23e3c0ae867cca0130e441e776c9955b9027c510 cve-icon cve-icon
https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2 cve-icon cve-icon
https://github.com/python/cpython/commit/4802b96a2cde58570c24c13ef3289490980961c5 cve-icon cve-icon
https://github.com/python/cpython/commit/e4846a93ac07a8ae9aa18203af0dd13d6e7a6995 cve-icon cve-icon
https://github.com/python/cpython/commit/f7fceed79ca1bceae8dbe5ba5bc8928564da7211 cve-icon cve-icon
https://github.com/python/cpython/issues/143916 cve-icon cve-icon cve-icon
https://github.com/python/cpython/pull/143917 cve-icon cve-icon cve-icon
https://mail.python.org/archives/list/security-announce@python.org/thread/BJ6QPHNSHJTS3A7CFV6IBMCAP2DWRVNT/ cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-0865 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-0865 cve-icon
History

Thu, 22 Jan 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 4.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:H/A:N'}

threat_severity

Moderate

Wed, 21 Jan 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 21 Jan 2026 11:30:00 +0000

Type Values Removed Values Added
First Time appeared Python
Python cpython
Vendors & Products Python
Python cpython

Tue, 20 Jan 2026 23:15:00 +0000

Type Values Removed Values Added
References

Tue, 20 Jan 2026 22:45:00 +0000

Type Values Removed Values Added
References

Tue, 20 Jan 2026 21:45:00 +0000

Type Values Removed Values Added
Description User-controlled header names and values containing newlines can allow injecting HTTP headers.
Title wsgiref.headers.Headers allows header newline injection
Weaknesses CWE-74
References
Metrics cvssV4_0

{'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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: PSF

Published:

Updated: 2026-01-21T16:14:52.038Z

Reserved: 2026-01-12T16:07:56.781Z

Link: CVE-2026-0865

cve-icon Vulnrichment

Updated: 2026-01-21T15:48:38.269Z

cve-icon NVD

Status : Received

Published: 2026-01-20T22:15:52.800

Modified: 2026-01-20T23:16:05.933

Link: CVE-2026-0865

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-01-20T21:26:15Z

Links: CVE-2026-0865 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-01-21T11:18:52Z

Weaknesses