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.
Related CPE's
a
python
python
10
References
https://github.com/python/cpython/issues/90309
ExploitIssue Tracking
https://github.com/python/cpython/pull/148848
Issue TrackingPatch
https://mail.python.org/archives/list/[email protected]/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/
Mailing ListVendor Advisory
CVSS impact metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1 · Medium
Information
Source identifier
Vulnerability status
Analyzed
Published
2026-04-22T20:16:42.617Z
5 months agoLast modified
2026-07-27T17:34:54.330Z
2 months ago