CVE-2026-6019

low

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.

References

https://mail.python.org/archives/list/[email protected]/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/

https://github.com/python/cpython/pull/148848

https://github.com/python/cpython/issues/90309

https://github.com/python/cpython/commit/f795e042043dfe26c42e1971d4502c1cdc4c65b8

https://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104

https://github.com/python/cpython/commit/3c59b8b53fc75c7f9578d16fb8201ceb43e8f76c

Details

Source: Mitre, NVD

Published: 2026-04-22

Updated: 2026-04-29

Risk Information

CVSS v2

Base Score: 4.7

Vector: CVSS2#AV:N/AC:L/Au:M/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 3.8

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Severity: Low

CVSS v4

Base Score: 2.1

Vector: 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

Severity: Low

EPSS

EPSS: 0.00039