inside the generated script element. Mitigation base64-encodes the cookie value to disallow escaping using cookie value.", "datePublished": "2026-04-22T19:28:08Z", "dateModified": "2026-06-10T18:58:07Z", "keywords": "CVE-2026-6019, vulnerability, CVE, security, CPython, Python Software Foundation", "about": { "@type": "SoftwareApplication", "name": "CPython", "applicationCategory": "SecurityApplication", "operatingSystem": "All" } }
CVE-2026-6019 LOW

CVE-2026-6019: BaseCookie.js_output() does not neutralize embedded characters

Vendor Python Software Foundation
Product CPython
Weakness CWE-150
Published April 22, 2026
Last update June 10, 2026

CVSS base score

2.1/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality
Integrity

CVSS 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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 22, 2026 CVE published
June 10, 2026 Record updated