CVE-2026-6019

BaseCookie.js_output() does not neutralize embedded characters

Published Apr 22, 2026 CVSS 4.0 · 2.1 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4827-1 python3.11 security update
Ubuntu USN Ubuntu USN USN-8509-1 Python vulnerabilities
History
Type Values Removed Values Added
First Time appeared Python python
CPEs cpe:2.3:a:python:cpython:*:*:*:*:*:*:*:* cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
Vendors & Products Python python
Type Values Removed Values Added
Weaknesses CWE-116
CPEs cpe:2.3:a:python:cpython:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'}

cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

Type Values Removed Values Added
Weaknesses CWE-79
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Python
Python cpython
Vendors & Products Python
Python cpython
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title BaseCookie.js_output() does not neutralize embedded characters
Weaknesses CWE-150
References
Metrics cvssV4_0

{'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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
PSF
Published
Updated
Nov 10, 2026, 12:40 PM
Reserved
Apr 9, 2026, 3:35 PM
Status
Modified
Published
Apr 22, 2026, 8:16 PM
Modified
Nov 10, 2026, 1:19 PM
Severity
Moderate
Public date
Apr 22, 2026, 7:28 PM