CVE-2026-6019

LOW

BaseCookie.js_output() does not neutralize embedded characters

Title source: cna

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 v4 2.1
EPSS 0.0004
EPSS Percentile 11.6%
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

Details

CWE
CWE-150
Status published
Products (1)
Python Software Foundation/CPython < 3.15.0
Published Apr 22, 2026
Tracked Since Apr 23, 2026