BaseCookie.js_output() does not neutralize embedded characters
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.
01
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-6019US | medium6.1 | — | ||
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 </scr… | ||||
02
references
External citations — patches, advisories, analysis.
- https://github.com/python/cpython/commit/3c59b8b53fc75c7f9578d16fb8201ceb43e8f76cFIX
- https://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104FIX
- https://github.com/python/cpython/commit/f795e042043dfe26c42e1971d4502c1cdc4c65b8FIX
- https://github.com/python/cpython/issues/90309EVIDENCE
- https://github.com/python/cpython/pull/148848FIX
- https://mail.python.org/archives/list/security-announce@python.org/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/ADVISORY
- https://nvd.nist.gov/vuln/detail/CVE-2026-6019WEB
scry
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