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 v3 6.1 MEDIUM

6.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/python/cpython/commit/3c59b8b53fc75c7f9578d16fb8201ceb43e8f76c	Patch
https://github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104	Patch
https://github.com/python/cpython/commit/f795e042043dfe26c42e1971d4502c1cdc4c65b8	Patch
https://github.com/python/cpython/issues/90309	Exploit Issue Tracking
https://github.com/python/cpython/pull/148848	Issue Tracking Patch
https://mail.python.org/archives/list/security-announce@python.org/thread/IVNWGV2BBNC3RHQAFS22UP4DY56SAXX3/	Mailing List Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:python:python::::::::
	cpe:2.3:a:python:python::::::::
	cpe:2.3:a:python:python:3.15.0:alpha1::::::
	cpe:2.3:a:python:python:3.15.0:alpha2::::::
	cpe:2.3:a:python:python:3.15.0:alpha3::::::
	cpe:2.3:a:python:python:3.15.0:alpha4::::::
	cpe:2.3:a:python:python:3.15.0:alpha5::::::
	cpe:2.3:a:python:python:3.15.0:alpha6::::::
	cpe:2.3:a:python:python:3.15.0:alpha7::::::
	cpe:2.3:a:python:python:3.15.0:alpha8::::::

History

No history.

Information

Published : 2026-04-22 20:16

Updated : 2026-07-27 17:34

NVD link : CVE-2026-6019

Mitre link : CVE-2026-6019

CVE.ORG link : CVE-2026-6019

JSON object : View

Products Affected

python

python

CWE

CWE-150

Improper Neutralization of Escape, Meta, or Control Sequences

CWE-116

Improper Encoding or Escaping of Output

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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."}], "lastModified": "2026-07-27T17:34:54.330", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "16DAC42F-7128-49F8-B799-78D78580EC70", "versionEndExcluding": "3.13.14"}, {"criteria": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E819F5F6-4D1E-4965-BAEA-B730ECE9713C", "versionEndIncluding": "3.14.4", "versionStartIncluding": "3.14.0"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A3327507-0B1D-4F28-A983-D07A2C8A7696"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C8AF17F1-A27F-4C98-BA5A-B4319710E8D1"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "24CF56B0-2F4E-42A2-B655-F493AA0A4815"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7184ABBA-B100-489E-B5C1-1C9EEC0546CA"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B6D4181B-3E1B-499B-AAB1-50868A6A6AD3"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha6:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A52F6DD2-717D-4E8C-8DB7-00890BC1ABAE"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha7:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8C46C55C-801E-4F86-B669-8E6A12B4AB6F"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha8:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5A8DF8E5-61F9-4899-BF40-41A17E223441"}], "operator": "OR"}]}], "sourceIdentifier": "cna@python.org"}