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.
- CVSS 4.0
- 2.1
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 - CVSS 3.1
- 6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 11% of CVEs (scores of 2026-10-26)
- CWEs
- CWE-116, CWE-150
- Published
- Modified
- Record from
- the NVD, synced
Affected
- 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