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CVE-2026-0865 | Mondoo Vulnerability Intelligence

Vulnerability IntelligenceCVE-2026-0865

CVE-2026-0865

MEDIUM5.9

wsgiref.headers.Headers allows header newline injection

Published Jan 20, 2026

Modified 7 months ago

Fix available

Details

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

Affected Packages

Python

Windows 10 (1507)Windows 10 (1607) / Server 2016Windows 10 (1703)Windows 10 (1709)Windows 10 (1803)

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python

Windows 10 (1507)Windows 10 (1607) / Server 2016Windows 10 (1703)Windows 10 (1709)Windows 10 (1803)

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.10

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.11

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.12

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.13

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.14

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.15

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.8

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

python@3.9

brew

Fixed in:

3.10.203.11.153.12.133.13.123.14.33.15.0a6

References

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/

https://www.cve.org/CVERecord?id=CVE-2026-0865

CVSS Analysis

CVSS v4.0

5.9

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Attack Requirements

PresentAT:P

Privileges Required

HighPR:H

User Interaction

NoneUI:N

Vulnerable System

Vuln. Confidentiality

NoneVC:N

Vuln. Integrity

HighVI:H

Vuln. Availability

NoneVA:N

Subsequent System

Subseq. Confidentiality

NoneSC:N

Subseq. Integrity

NoneSI:N

Subseq. Availability

NoneSA:N

5.9/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

Weakness Type (CWE)

Input Validation

Ecosystems(25)

Windows 10 (1507)Windows 10 (1607) / Server 2016 Windows 10 (1703)Windows 10 (1709)Windows 10 (1803)

Timeline

PublishedJan 20, 2026

ModifiedMar 3, 2026