Skip to content
Fencer Intel
medium 5.9

CVE-2026-0865 json

wsgiref.headers.Headers allows header newline injection

published 9mo ago modified 4mo ago also BIT-libpython-2026-0865 , BIT-python-2026-0865 , BIT-python-min-2026-0865 , EUVD-2026-3520

cvss
5.9
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 46%
public exploits
0
none known

Summary

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

Patch / fix

  • bitnami libpython 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3
  • bitnami python 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3
  • bitnami python-min 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3
  • Python Software Foundation CPython 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3, 3.15.0a6
  • pypy3 Debian 14 7.3.21+dfsg-1
  • python3.11 Debian 12 3.11.2-6+deb12u7
  • python3.13 Debian 13 3.13.5-2+deb13u1
  • python3.14 Debian 14 3.14.3-1

debian advisories DEBIAN-CVE-2026-0865

  • python3.10 Ubuntu 22.04 LTS 3.10.12-1~22.04.14
  • python3.12 Ubuntu 24.04 LTS 3.12.3-1ubuntu0.11
  • python3.13 Ubuntu 25.10 3.13.7-1ubuntu0.3
  • python3.14 Ubuntu 25.10 3.14.0-1ubuntu0.2
  • python2.7 Ubuntu Pro 14.04 LTS 2.7.6-8ubuntu0.6+esm29
  • python2.7 Ubuntu Pro 16.04 LTS 2.7.12-1ubuntu0~16.04.18+esm19
  • python2.7 Ubuntu Pro 18.04 LTS 2.7.17-1~18.04ubuntu1.13+esm14
  • python2.7 Ubuntu Pro 22.04 LTS 2.7.18-13ubuntu1.5+esm8

ubuntu advisories UBUNTU-CVE-2026-0865

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python3.14 RHEL 9 3.14.4-2.el9_8
  • python3.14-idle RHEL 9 3.14.4-2.el9_8
  • python3.14-libs RHEL 9 3.14.4-2.el9_8
  • python3.14-test RHEL 9 3.14.4-2.el9_8
  • python3.14-tkinter RHEL 9 3.14.4-2.el9_8
  • python3.14-freethreading RHEL 9 3.14.4-2.el9_8
  • python3.14-freethreading-idle RHEL 9 3.14.4-2.el9_8
  • python3.14-freethreading-libs RHEL 9 3.14.4-2.el9_8

red hat advisories RHSA-2026:19176RHSA-2026:19019RHSA-2026:18957RHSA-2026:18958RHSA-2026:18693RHSA-2026:8822

  • python311 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 3.11.15-150400.9.80.1
  • python311-core SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 3.11.15-150400.9.80.1
  • python311-documentation SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 3.11.15-150400.9.80.1
  • python311 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 +1 more 3.11.15-150600.3.53.1
  • python311-core SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 +2 more 3.11.15-150600.3.53.1
  • python311-documentation openSUSE Leap 15.6 3.11.15-150600.3.53.1
  • python311 Linux Micro 6.1 3.11.15-slfo.1.1_1.1
  • python311-core Linux Micro 6.1 3.11.15-slfo.1.1_1.1

suse advisories SUSE-SU-2026:1117-1SUSE-SU-2026:1349-1SUSE-SU-2026:20768-1SUSE-SU-2026:20796-1SUSE-SU-2026:20665-1SUSE-SU-2026:20710-1

  • python313 openSUSE Leap 16.0 3.13.12-160000.1.1
  • python313-core openSUSE Leap 16.0 3.13.12-160000.1.1
  • python313-nogil openSUSE Leap 16.0 3.13.12-160000.1.1
  • python313-documentation openSUSE Leap 16.0 3.13.12-160000.1.1
  • python313-nogil-nogil-core openSUSE Leap 16.0 3.13.12-160000.1.1
  • python311 openSUSE Tumbleweed 3.11.14-4.1
  • python312 openSUSE Tumbleweed 3.12.12-5.1
  • python313 openSUSE Tumbleweed 3.13.12-1.1

opensuse advisories openSUSE-SU-2026:20254-1openSUSE-SU-2026:10221-1openSUSE-SU-2026:10222-1openSUSE-SU-2026:10223-1openSUSE-SU-2026:10206-1openSUSE-SU-2026:10200-1

  • python3.14 AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-idle AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-libs AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-test AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-tkinter AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-freethreading AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-freethreading-idle AlmaLinux 10 3.14.4-2.el10_2
  • python3.14-freethreading-libs AlmaLinux 10 3.14.4-2.el10_2

almalinux advisories ALSA-2026:19019ALSA-2026:19176ALSA-2026:4713ALSA-2026:4463ALSA-2026:4473ALSA-2026:4168

  • python3.14 Rocky Linux 9 3.14.4-2.el9_8
  • python3.14 Rocky Linux 10 3.14.4-2.el10_2
  • python3 Rocky Linux 8 3.6.8-73.el8_10.rocky.0
  • python3.12 Rocky Linux 10 3.12.12-3.el10_1.1
  • python3.11 Rocky Linux 8 3.11.13-5.el8_10
  • python3.12 Rocky Linux 8 3.12.12-3.el8_10
  • python3.9 Rocky Linux 9 3.9.25-3.el9_7.1

rocky linux advisories RLSA-2026:19176RLSA-2026:19019RLSA-2026:2128RLSA-2026:4713RLSA-2026:4473RLSA-2026:4463

  • python3 Azure Linux 3.0 3.12.9-8
  • python3 CBL-Mariner 2.0 3.9.19-19

azure linux advisories AZL-75032AZL-75053

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-0865 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-0865 updated cvss 4.5

cpython: wsgiref.headers.Headers allows header newline injection in Python

  • Red Hat Enterprise Linux 6 python, tkinter, python-libs, python-test, python-tools Red Hat Enterprise Linux 7 python, firefox, python3, tkinter, python-libs, python-test, +5 more Red Hat Enterprise Linux 8 numpy, scipy, PyYAML, firefox, mod_wsgi, python36, +72 more Red Hat Enterprise Linux 9 firefox, firefox-x11 Red Hat Enterprise Linux 10 firefox Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/bootc-azure-cuda-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ceph Storage 8 rhceph 1774002867
    fixed: vendor fix RHSA-2026:5606
  • Red Hat CodeReady Linux Builder EUS (v.9.4) python3.11 3.11.7-1.el9_4.11, python3.11-idle 3.11.7-1.el9_4.11, python3.11-test 3.11.7-1.el9_4.11, python3.11-tkinter 3.11.7-1.el9_4.11
    fixed: vendor fix RHSA-2026:6253
  • Red Hat Enterprise Linux AppStream (v. 8) python3.11 3.11.13-5.el8_10, python3.12 3.12.12-3.el8_10, python3-idle 3.6.8-73.el8_10, python3-test 3.6.8-73.el8_10, platform-python 3.6.8-73.el8_10, python3-tkinter 3.6.8-73.el8_10, +6 more
    fixed: vendor fix RHSA-2026:2128
  • Red Hat Enterprise Linux AppStream (v. 9) python3.14 3.14.4-2.el9_8, python3.11 3.11.13-7.el9_8, python3.12 3.12.12-6.el9_8, python3-tkinter 3.9.25-5.el9_8, python3.14-libs 3.14.4-2.el9_8, python3.11-libs 3.11.13-7.el9_8, +7 more
    fixed: vendor fix RHSA-2026:4168
  • Red Hat Enterprise Linux AppStream (v. 10) python3.14 3.14.4-2.el10_2, python3.14-libs 3.14.4-2.el10_2, python3-tkinter 3.12.12-3.el10_1.1, python3.14-tkinter 3.14.4-2.el10_2, python-unversioned-command 3.12.12-3.el10_1.1
    fixed: vendor fix RHSA-2026:4713
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) python3.11 3.11.7-1.el9_4.11, python3.11-libs 3.11.7-1.el9_4.11, python3.11-tkinter 3.11.7-1.el9_4.11
    fixed: vendor fix RHSA-2026:6253
  • Red Hat Enterprise Linux BaseOS (v. 8) python3 3.6.8-73.el8_10, python3-libs 3.6.8-73.el8_10, python3-test 3.6.8-73.el8_10, platform-python 3.6.8-73.el8_10
    fixed: vendor fix RHSA-2026:2128
show 8 more
  • Red Hat Enterprise Linux BaseOS (v. 9) python3 3.9.25-5.el9_8, python3 3.9.25-3.el9_7.1, python3.9 3.9.25-5.el9_8, python3.9 3.9.25-3.el9_7.1, python3-libs 3.9.25-5.el9_8, python3-libs 3.9.25-3.el9_7.1
    fixed: vendor fix RHSA-2026:4168
  • Red Hat Enterprise Linux BaseOS (v. 10) python3 3.12.12-3.el10_1.1, python3.12 3.12.12-3.el10_1.1, python3-libs 3.12.12-3.el10_1.1
    fixed: vendor fix RHSA-2026:4713
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3 3.9.25-5.el9_8, python3 3.9.25-3.el9_7.1, python3.14 3.14.4-2.el9_8, python3.11 3.11.13-7.el9_8, python3.12 3.12.12-6.el9_8, python3-idle 3.9.25-5.el9_8, +19 more
    fixed: vendor fix RHSA-2026:4168
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) python3-idle 3.12.12-3.el10_1.1, python3-test 3.12.12-3.el10_1.1, python3.14-idle 3.14.4-2.el10_2, python3.14-test 3.14.4-2.el10_2, python3.14-freethreading 3.14.4-2.el10_2, python3.14-freethreading-idle 3.14.4-2.el10_2, +3 more
    fixed: vendor fix RHSA-2026:4713
  • Red Hat Enterprise Linux CRB (v. 8) python3.11 3.11.13-5.el8_10, python3.12 3.12.12-3.el8_10, python3.11-idle 3.11.13-5.el8_10, python3.11-test 3.11.13-5.el8_10, python3.12-idle 3.12.12-3.el8_10, python3.12-test 3.12.12-3.el8_10, +2 more
    fixed: vendor fix RHSA-2026:4473
  • Red Hat Hardened Images python3 3.14.4-1.hum1, python3.14 3.14.4-1.hum1, python3.11 3.11.15-4.hum1, python3.12 3.12.13-3.hum1, python3.13 3.13.13-1.hum1, python3-idle 3.14.4-1.hum1, +22 more
    fixed: vendor fix RHSA-2026:7661
  • Red Hat Update Infrastructure 5 rhui5 1773668803, rhui5 1773670073, rhui5 1773670137, rhui5 1773672059, rhui5/cds-rhel9 1779798159, rhui5/rhua-rhel9 1779798222, +5 more
    fixed: vendor fix RHSA-2026:58981
  • Red Hat Update Infrastructure 5 rhui5/cds-tp-rhel9 1787241206
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
9mo ago

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 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
CNA 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
bitnami libpython
<3.10.20
>=3.11.0, <3.11.15
>=3.12.0, <3.12.13
>=3.13.0, <3.13.12
>=3.14.0, <3.14.3
3.10.20
3.11.15
3.12.13
3.13.12
3.14.3
bitnami python
<3.10.20
>=3.11.0, <3.11.15
>=3.12.0, <3.12.13
>=3.13.0, <3.13.12
>=3.14.0, <3.14.3
3.10.20
3.11.15
3.12.13
3.13.12
3.14.3
bitnami python-min
<3.10.20
>=3.11.0, <3.11.15
>=3.12.0, <3.12.13
>=3.13.0, <3.13.12
>=3.14.0, <3.14.3
3.10.20
3.11.15
3.12.13
3.13.12
3.14.3

Affected products

  • Python Software Foundation CPython

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.