Incomplete control character validation in http.cookies
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: 9 fixed, 6 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().
Why it matters now
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 3.10.21; 3.11.0 to before 3.11.16; 3.12.0 to before 3.12.14; 3.13.0 to before 3.13.13; 3.14.0 to before 3.14.4; 3.15.0a1 to before 3.15.0a8 | 3.10.21, 3.11.16, 3.12.14, 3.13.13, 3.14.4, 3.15.0a8 | Patch available | CNA |
- CPython VendorPython Software Foundation Affected before 3.10.21; 3.11.0 to before 3.11.16; 3.12.0 to before 3.12.14; 3.13.0 to before 3.13.13; 3.14.0 to before 3.14.4; 3.15.0a1 to before 3.15.0a8 Fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.13, 3.14.4, 3.15.0a8 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:python:python:*:*:*:*:*:*:*:* | before 3.13.13; 3.14.0 to before 3.14.4 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha1:*:*:*:*:*:* | 3.15.0 alpha1 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha2:*:*:*:*:*:* | 3.15.0 alpha2 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha3:*:*:*:*:*:* | 3.15.0 alpha3 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha4:*:*:*:*:*:* | 3.15.0 alpha4 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha5:*:*:*:*:*:* | 3.15.0 alpha5 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha6:*:*:*:*:*:* | 3.15.0 alpha6 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.15.0:alpha7:*:*:*:*:*:* | 3.15.0 alpha7 | Vulnerable | python-pillow |
- cpe:2.3:a:python:python:*:*:*:*:*:*:*:* Versions before 3.13.13; 3.14.0 to before 3.14.4 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha1:*:*:*:*:*:* Versions 3.15.0 alpha1 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha2:*:*:*:*:*:* Versions 3.15.0 alpha2 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha3:*:*:*:*:*:* Versions 3.15.0 alpha3 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha4:*:*:*:*:*:* Versions 3.15.0 alpha4 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha5:*:*:*:*:*:* Versions 3.15.0 alpha5 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha6:*:*:*:*:*:* Versions 3.15.0 alpha6 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.15.0:alpha7:*:*:*:*:*:* Versions 3.15.0 alpha7 Vulnerable ·python-pillow
Remediation
- Fix · CNA CPython (Python Software Foundation) Fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.13, 3.14.4, 3.15.0a8
Red Hat 11 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-2026:19176 Released 2026-05-19 · Red Hat rating Importantpython3.14 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 8 more Red Hat advisories
- 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
- 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-2026:19019 Released 2026-05-19 · Red Hat rating Importantpython3.14 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-2026:10950 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
- RHSA-2026:8824 Released 2026-04-17 · Red Hat rating ImportantRed 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 ImportantRed 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 ImportantRed 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 ImportantRed 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
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Python Software Foundation CPython 3.10.21, 3.11.16 and 4 more versions
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-03671 Stack overflow parsing XML with deeply nested DTD content modelsPriority LOW 28
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| 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-2026:19019, RHSA-2026:19064 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:10950 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:19176, 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-2026:19019, RHSA-2026:19064 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:19176, RHSA-2026:19177 |
| Red Hat Hardened Images | Fixed | RHSA-2026:7443, RHSA-2026:7661, RHSA-2026:8822, RHSA-2026:8824 |
| 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-2026-3644
- 2026-10-03 Alias added: GHSA-vf33-88pf-hwp3
- 2026-11-06 Affected versions changed · Red Hat
References
Patch 7
- https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4
- https://github.com/python/cpython/pull/145600
- https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd
- https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd
- https://github.com/python/cpython/commit/556aa098e738b127c714866f819b4abe2f7593d8
- https://github.com/python/cpython/commit/dae4b1a21f8df4570e30986affd61bbe4ade4cef
- https://github.com/python/cpython/commit/3974092b037f9a3b000fb15b48ea61ce3b25d330
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-2026-3644 · CVE Program
- CVE-2026-3644 · NVD
- FIRST EPSS
- GHSA-vf33-88pf-hwp3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-3644 · 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