CVE-2026-6019
BaseCookie.js_output() does not neutralize embedded characters
- State
- Published
- Severity
- 2.1 Low
- Published
- Apr 22, 2026
- Updated
- Jun 10, 2026
- Reserved
- Apr 9, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 2.1 Low | 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 |
Weaknesses
- CWE-150 Improper neutralization of escape, meta, or control sequences
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/pull/148848patch
- https://github.com/python/cpython/issues/90309issue-tracking
- https://mail.python.org/archives/list/security-announce@python.org/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/vendor-advisory
- https://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104patch
- https://github.com/python/cpython/commit/3c59b8b53fc75c7f9578d16fb8201ceb43e8f76cpatch
- https://github.com/python/cpython/commit/f795e042043dfe26c42e1971d4502c1cdc4c65b8patch
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