CVE-2026-6019
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.
Weakness
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.
Affected products
- python python
References
- https://github.com/python/cpython/commit/3c59b8b53fc75c7f9578d16fb8201ceb43e8f76c
- https://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104
- https://github.com/python/cpython/commit/f795e042043dfe26c42e1971d4502c1cdc4c65b8
- https://github.com/python/cpython/issues/90309
- https://github.com/python/cpython/pull/148848
- https://mail.python.org/archives/list/[email protected]/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/
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