BaseCookie.js_output() does not neutralize embedded characters_CVE-2026-6019

2.1 / 10

LOW

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

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.

Basic Information

ID CVE-2026-6019

Source PSF

Published Apr 22, 2026 at 19:28

Modified Apr 22, 2026 at 20:02

Affected Product

Vendor Python Software Foundation

Product CPython

Affected Versions Python Software Foundation CPython 0

CWE Classification

CWE-150

References

{
    "lastseen": "",
    "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.",
    "published": "2026-04-22T19:28:08.720Z",
    "modified": "2026-04-22T20:02:34.468Z",
    "type": "cve",
    "title": "BaseCookie.js_output() does not neutralize embedded characters",
    "source": "PSF",
    "references": "https://github.com/python/cpython/pull/148848\nhttps://github.com/python/cpython/issues/90309\nhttps://mail.python.org/archives/list/[email protected]/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/\nhttps://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104",
    "id": "CVE-2026-6019",
    "bulletinFamily": "",
    "cwe": [
        "CWE-150"
    ],
    "cvelist": null,
    "sourceData": "Python Software Foundation CPython 0",
    "sourceHref": "",
    "cvss": {
        "score": 2.1,
        "severity": "LOW",
        "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "CPython",
    "version": "0",
    "vendor": "Python Software Foundation",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}