CVE-2026-6019
BaseCookie.js_output() does not neutralize embedded characters
LOW 2.1
At a glance
- Source
- NVD
- EPSS
- EPSS 0.21 % · percentile 11 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- PSF
- NVD status
- Analyzed
Description
http.cookies.Morsel.js_output() returns an inline <script> snippet and only escapes " for JavaScript string context. It does not neutralize the HTML parser-sensitive sequence </script> inside the generated script element. Mitigation base64-encodes the cookie value to disallow escaping using cookie value.
Weaknesses (CWE)
References
- https://github.com/python/cpython/pull/148848
- https://github.com/python/cpython/issues/90309
- https://mail.python.org/archives/list/security-announce@python.org/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/
- https://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104
- https://github.com/python/cpython/commit/3c59b8b53fc75c7f9578d16fb8201ceb43e8f76c
- https://github.com/python/cpython/commit/f795e042043dfe26c42e1971d4502c1cdc4c65b8
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | LOW 2.1 | CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | PSF |
| CVSS 4.0 | LOW 2.1 | CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/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 | NVD · cna@python.org (Secondary) |
| CVSS 3.1 | MEDIUM 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-25079
- GCVE · GCVE-0-2026-6019
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0482 — Vulnérabilité dans CPython · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*< 3.13.14cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.14.0 ≤ 3.14.4cpe:2.3:a:python:python:3.15.0:alpha1:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha2:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha3:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha4:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha5:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha6:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha7:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha8:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Python Software Foundation · CPython | affected 0 < 3.13.14 ; affected 3.14.0a1 < 3.14.5rc1 ; affected 3.15.0a1 < 3.15.0b1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |