Read the docs
TI-2026-00646 Aliases CVE-2026-0865GHSA-5mc7-p6pj-r3f5

wsgiref.headers.Headers allows header newline injection

Priority LOW 27CWE-74Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 14 fixed, 6 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

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

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00554 46th percentileScored 2026-11-07
Fix Partial CPython (Python Software Foundation): 3.10.20, 3.11.15, 3.12.13 +3Red Hat: 19 advisoriesRed Hat: 14 fixed, 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Python Software FoundationCPythonbefore 3.10.20; 3.11.0 to before 3.11.15; 3.12.0 to before 3.12.13; 3.13.0 to before 3.13.12; 3.14.0 to before 3.14.3; 3.15.0a1 to before 3.15.0a63.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3, 3.15.0a6Patch availableCNA
  • CPython VendorPython Software Foundation Affected before 3.10.20; 3.11.0 to before 3.11.15; 3.12.0 to before 3.12.13; 3.13.0 to before 3.13.12; 3.14.0 to before 3.14.3; 3.15.0a1 to before 3.15.0a6 Fixed in 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3, 3.15.0a6 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*——python-pillow
  • cpe:2.3:a:python:python:*:*:*:*:*:*:*:* Versions — — ·python-pillow

Remediation

  • Fix · CNA CPython (Python Software Foundation) Fixed in 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3, 3.15.0a6

Red Hat 19 advisories

  • RHSA-2026:58981 Released 2026-08-24 · Red Hat rating Critical
    Red Hat Update Infrastructure 5.3 Technology Preview security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-kubernetes-tp-rhel9, registry.redhat.io/rhui5/installer-tp-rhel9, registry.redhat.io/rhui5/rhua-tp-rhel9
  • RHSA-2026:21275 Released 2026-05-27 · Red Hat rating Critical
    Red Hat Update Infrastructure 5.1 security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9, registry.redhat.io/rhui5/installer-rhel9 +1
  • RHSA-2026:19176 Released 2026-05-19 · Red Hat rating Important
    python3.14 security update
    • Red Hat Enterprise Linux AppStream (v. 9) python3.14-3.14.4-2.el9_8, python3.14-devel-3.14.4-2.el9_8, python3.14-libs-3.14.4-2.el9_8 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3.14-3.14.4-2.el9_8, python3.14-debug-3.14.4-2.el9_8, python3.14-freethreading-3.14.4-2.el9_8 +9
Show 16 more Red Hat advisories
  • RHSA-2026:18957 Released 2026-05-19 · Red Hat rating Moderate
    python3.11 security update
    • Red Hat Enterprise Linux AppStream (v. 9) python3.11-3.11.13-7.el9_8, python3.11-devel-3.11.13-7.el9_8, python3.11-libs-3.11.13-7.el9_8 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3.11-3.11.13-7.el9_8, python3.11-debug-3.11.13-7.el9_8, python3.11-idle-3.11.13-7.el9_8 +2
  • RHSA-2026:18958 Released 2026-05-19 · Red Hat rating Moderate
    python3.12 security update
    • Red Hat Enterprise Linux AppStream (v. 9) python3.12-3.12.12-6.el9_8, python3.12-devel-3.12.12-6.el9_8, python3.12-libs-3.12.12-6.el9_8 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3.12-3.12.12-6.el9_8, python3.12-debug-3.12.12-6.el9_8, python3.12-idle-3.12.12-6.el9_8 +2
  • RHSA-2026:19019 Released 2026-05-19 · Red Hat rating Important
    python3.14 security update
    • Red Hat Enterprise Linux AppStream (v. 10) python3.14-3.14.4-2.el10_2, python3.14-devel-3.14.4-2.el10_2, python3.14-libs-3.14.4-2.el10_2 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) python3.14-debug-3.14.4-2.el10_2, python3.14-freethreading-3.14.4-2.el10_2, python3.14-freethreading-debug-3.14.4-2.el10_2 +7
  • RHSA-2026:18693 Released 2026-05-19 · Red Hat rating Moderate
    python3.9 security update
    • Red Hat Enterprise Linux AppStream (v. 9) python-unversioned-command-3.9.25-5.el9_8, python3-devel-3.9.25-5.el9_8, python3-tkinter-3.9.25-5.el9_8
    • Red Hat Enterprise Linux BaseOS (v. 9) python3-3.9.25-5.el9_8, python3-libs-3.9.25-5.el9_8, python3.9-3.9.25-5.el9_8
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3-3.9.25-5.el9_8, python3-debug-3.9.25-5.el9_8, python3-idle-3.9.25-5.el9_8 +2
  • RHSA-2026:8824 Released 2026-04-17 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images python3.12-3.12.13-3.hum1@aarch64, python3.12-3.12.13-3.hum1@src, python3.12-3.12.13-3.hum1@x86_64 +12
  • RHSA-2026:8822 Released 2026-04-17 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images python3.11-3.11.15-4.hum1@aarch64, python3.11-3.11.15-4.hum1@src, python3.11-3.11.15-4.hum1@x86_64 +12
  • RHSA-2026:7661 Released 2026-04-11 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images python-unversioned-command-3.14.4-1.hum1@noarch@public-hummingbird-aarch64-rpms, python-unversioned-command-3.14.4-1.hum1@noarch@public-hummingbird-x86_64-rpms, python3-3.14.4-1.hum1@aarch64 +28
  • RHSA-2026:7443 Released 2026-04-10 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images python3.13-3.13.13-1.hum1@aarch64, python3.13-3.13.13-1.hum1@src, python3.13-3.13.13-1.hum1@x86_64 +16
  • RHSA-2026:6253 Released 2026-03-31 · Red Hat rating Moderate
    python3.11 security update
    • Red Hat CodeReady Linux Builder EUS (v.9.4) python3.11-3.11.7-1.el9_4.11, python3.11-debug-3.11.7-1.el9_4.11, python3.11-idle-3.11.7-1.el9_4.11 +2
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) python3.11-3.11.7-1.el9_4.11, python3.11-devel-3.11.7-1.el9_4.11, python3.11-libs-3.11.7-1.el9_4.11 +1
  • RHSA-2026:5606 Released 2026-03-24 · Red Hat rating Important
    Red Hat Ceph Storage
    • Red Hat Ceph Storage 8 registry.redhat.io/rhceph/rhceph-8-rhel9
  • RHSA-2026:4943 Released 2026-03-18 · Red Hat rating Important
    Red Hat Update Infrastructure 5.1 security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9, registry.redhat.io/rhui5/installer-rhel9 +1
  • RHSA-2026:4713 Released 2026-03-17 · Red Hat rating Moderate
    python3.12 security update
    • Red Hat Enterprise Linux AppStream (v. 10) python-unversioned-command-3.12.12-3.el10_1.1, python3-devel-3.12.12-3.el10_1.1, python3-tkinter-3.12.12-3.el10_1.1
    • Red Hat Enterprise Linux BaseOS (v. 10) python3-3.12.12-3.el10_1.1, python3-libs-3.12.12-3.el10_1.1, python3.12-3.12.12-3.el10_1.1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) python3-debug-3.12.12-3.el10_1.1, python3-idle-3.12.12-3.el10_1.1, python3-test-3.12.12-3.el10_1.1
  • RHSA-2026:4473 Released 2026-03-12 · Red Hat rating Moderate
    python3.11 security update
    • Red Hat Enterprise Linux AppStream (v. 8) python3.11-3.11.13-5.el8_10, python3.11-devel-3.11.13-5.el8_10, python3.11-libs-3.11.13-5.el8_10 +2
    • Red Hat Enterprise Linux CRB (v. 8) python3.11-3.11.13-5.el8_10, python3.11-debug-3.11.13-5.el8_10, python3.11-idle-3.11.13-5.el8_10 +2
  • RHSA-2026:4463 Released 2026-03-12 · Red Hat rating Moderate
    python3.12 security update
    • Red Hat Enterprise Linux AppStream (v. 8) python3.12-3.12.12-3.el8_10, python3.12-devel-3.12.12-3.el8_10, python3.12-libs-3.12.12-3.el8_10 +2
    • Red Hat Enterprise Linux CRB (v. 8) python3.12-3.12.12-3.el8_10, python3.12-debug-3.12.12-3.el8_10, python3.12-idle-3.12.12-3.el8_10 +2
  • RHSA-2026:4168 Released 2026-03-10 · Red Hat rating Moderate
    python3.9 security update
    • Red Hat Enterprise Linux AppStream (v. 9) python-unversioned-command-3.9.25-3.el9_7.1, python3-devel-3.9.25-3.el9_7.1, python3-tkinter-3.9.25-3.el9_7.1
    • Red Hat Enterprise Linux BaseOS (v. 9) python3-3.9.25-3.el9_7.1, python3-libs-3.9.25-3.el9_7.1, python3.9-3.9.25-3.el9_7.1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3-3.9.25-3.el9_7.1, python3-debug-3.9.25-3.el9_7.1, python3-idle-3.9.25-3.el9_7.1 +2
  • RHSA-2026:2128 Released 2026-02-05 · Red Hat rating Moderate
    python3 security update
    • Red Hat Enterprise Linux AppStream (v. 8) platform-python-3.6.8-73.el8_10, platform-python-debug-3.6.8-73.el8_10, platform-python-devel-3.6.8-73.el8_10 +3
    • Red Hat Enterprise Linux BaseOS (v. 8) platform-python-3.6.8-73.el8_10, python3-3.6.8-73.el8_10, python3-libs-3.6.8-73.el8_10 +1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Python Software Foundation CPython 3.10.20, 3.11.15 and 4 more versions

    4 records Highest priority Priority LOW 4 LOW

    Other records, highest priority first

    • TI-2025-13957 Header injection via newlines in data URL mediatypePriority LOW 28
    • TI-2026-00465 Header injection in http.cookies.MorselPriority LOW 27
    • TI-2025-10506 Folding email comments of unfoldable characters doesn't preserve parenthesisPriority LOW 27
    Show all 4 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet: Fix deferred
Red Hat Ceph Storage 8Fixed RHSA-2026:5606
Red Hat CodeReady Linux Builder EUS (v.9.4)Fixed RHSA-2026:6253
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:19019, RHSA-2026:4713
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:2128, RHSA-2026:4463, RHSA-2026:4473
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:18693, RHSA-2026:18957, RHSA-2026:18958, RHSA-2026:19176, RHSA-2026:4168
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2026:6253
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:4713
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:2128
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:18693, RHSA-2026:4168
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:4463, RHSA-2026:4473
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:19019, RHSA-2026:4713
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:18693, RHSA-2026:18957, RHSA-2026:18958, RHSA-2026:19176, RHSA-2026:4168
Red Hat Hardened ImagesFixed RHSA-2026:7443, RHSA-2026:7661, RHSA-2026:8822, RHSA-2026:8824
Red Hat Update Infrastructure 5Fixed RHSA-2026:21275, RHSA-2026:4943, RHSA-2026:58981
Not affected: 1 product
  • Red Hat Update Infrastructure 5

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-0865
  2. 2026-10-03 Alias added: GHSA-5mc7-p6pj-r3f5

References

Patch 13

Advisory 1

Other 1

  • TI-2024-07037 Quadratic complexity parsing cookies with backslashes CVSS 3.1HIGH 7.5
  • TI-2024-11791 Bypass extraction filter to modify file metadata outside extraction directory CVSS 3.1MEDIUM 5.3
  • TI-2024-00411 Quoted zip-bomb protection for zipfile CVSS 3.1MEDIUM 6.2
  • TI-2026-13296 `HTTPPasswordMgr` can send saved HTTPS credentials via HTTP because of incorrect scheme matching CVSS 4.0MEDIUM 6.0
  • TI-2024-06422 Email header injection due to unquoted newlines CVSS 3.1MEDIUM 5.5
  • TI-2026-04606 Possible to hijack modules in current working directory CVSS 4.0MEDIUM 5.6
See all 83 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences