BaseCookie.js_output() does not neutralize embedded characters
Summary
| CVE | CVE-2026-6019 |
|---|---|
| State | PUBLISHED |
| Assigner | PSF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-22 20:16:42 UTC |
| Updated | 2026-04-22 21:23:52 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 2.1 LOW from [email protected]
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-150 | CWE-150 CWE-150 Improper neutralization of escape, meta, or control sequences
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 2.1 | 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/E:X/C... |
| 4.0 | CNA | CVSS | 2.1 | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
HighUser Interaction
NoneConfidentiality
LowIntegrity
LowAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Python Software Foundation | CPython | affected 3.15.0 python | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/python/cpython/pull/148848 | [email protected] | github.com | |
| mail.python.org/archives/list/[email protected]/thread/IVNWGV2BBNC... | [email protected] | mail.python.org | |
| github.com/python/cpython/commit/76b3923d688c0efc580658476c5f525ec8735104 | [email protected] | github.com | |
| github.com/python/cpython/issues/90309 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: oolongeya (https://github.com/komi22) (en)
CNA: Seth Larson (https://github.com/sethmlarson) (en)
There are currently no legacy QID mappings associated with this CVE.