Header injection in http.cookies.Morsel
Priority LOW 27CWE-93Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- Low · High · None
- Fix status
- Partial Red Hat: 8 fixed, 7 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTTP headers into messages. Patch rejects all control characters within cookie names, values, and parameters.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0048 41st percentileScored 2026-11-07
Fix Partial CPython (Python Software Foundation): 3.10.20, 3.11.15, 3.12.13 +3Red Hat: 5 advisoriesRed Hat: 8 fixed, 7 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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Python Software Foundation | CPython | 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 | 3.10.20, 3.11.15, 3.12.13, 3.13.12, 3.14.3, 3.15.0a6 | Patch available | CNA |
- 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.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| 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 5 advisories
- RHSA-2026:58981 Released 2026-08-24 · Red Hat rating CriticalRed 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 CriticalRed 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-2026:19177 Released 2026-05-19 · Red Hat rating Importantpython3.12 security update
- Red Hat Enterprise Linux AppStream (v. 9) python3.12-3.12.13-2.el9_8, python3.12-devel-3.12.13-2.el9_8, python3.12-libs-3.12.13-2.el9_8 +1
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3.12-3.12.13-2.el9_8, python3.12-debug-3.12.13-2.el9_8, python3.12-idle-3.12.13-2.el9_8 +2
Show 2 more Red Hat advisories
- RHSA-2026:19064 Released 2026-05-19 · Red Hat rating Importantpython3.12 security update
- Red Hat Enterprise Linux AppStream (v. 10) python-unversioned-command-3.12.13-2.el10_2, python3-devel-3.12.13-2.el10_2, python3-tkinter-3.12.13-2.el10_2
- Red Hat Enterprise Linux BaseOS (v. 10) python3-3.12.13-2.el10_2, python3-libs-3.12.13-2.el10_2, python3.12-3.12.13-2.el10_2
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) python3-debug-3.12.13-2.el10_2, python3-idle-3.12.13-2.el10_2, python3-test-3.12.13-2.el10_2
- RHSA-2026:10950 Released 2026-04-27 · Red Hat rating Importantpython3.12 security update
- Red Hat Enterprise Linux AppStream (v. 8) python3.12-3.12.13-2.el8_10, python3.12-devel-3.12.13-2.el8_10, python3.12-libs-3.12.13-2.el8_10 +2
- Red Hat Enterprise Linux CRB (v. 8) python3.12-3.12.13-2.el8_10, python3.12-debug-3.12.13-2.el8_10, python3.12-idle-3.12.13-2.el8_10 +2
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-2026-00646 wsgiref.headers.Headers allows header newline injectionPriority LOW 27
- TI-2025-10506 Folding email comments of unfoldable characters doesn't preserve parenthesisPriority LOW 27
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | — |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:19064 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:10950 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:19177 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:19064 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:10950 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:19064 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:19177 |
| Red Hat Update Infrastructure 5 | Fixed | RHSA-2026:21275, RHSA-2026:58981 |
Not affected: 1 product
- Red Hat Update Infrastructure 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-0672
- 2026-10-03 Alias added: GHSA-x85f-j5v8-5vrv
- 2026-11-06 Affected versions changed · Red Hat
References
Patch 7
- https://github.com/python/cpython/pull/143920
- https://github.com/python/cpython/commit/95746b3a13a985787ef53b977129041971ed7f70
- https://github.com/python/cpython/commit/712452e6f1d4b9f7f8c4c92ebfcaac1705faa440
- https://github.com/python/cpython/commit/62700107418eb2cca3fc88da036a243ea975f172
- https://github.com/python/cpython/commit/7852d72b653fea0199acf5fc2a84f6f8b84eba8d
- https://github.com/python/cpython/commit/918387e4912d12ffc166c8f2a38df92b6ec756ca
- https://github.com/python/cpython/commit/b1869ff648bbee0717221d09e6deff46617f3e85
Advisory 1
More Python Software Foundation vulnerabilities
- 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
Sources
- CVE-2026-0672 · CVE Program
- CVE-2026-0672 · NVD
- FIRST EPSS
- GHSA-x85f-j5v8-5vrv · GitHub Advisory Database · CC BY 4.0
- CVE-2026-0672 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences