CVE-2026-16052

EUVD-2026-124537
The http.cookies.Morsel class allows separator semicolons in attribute
values
and includes them verbatim in all output formats. An attacker who can
control
these values could use this to relax the cookie's Domain or SameSite
restrictions.
Injection
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
PSFCNA
2.3 LOW
NETWORK
LOW
NONE
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/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
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
pythoncpython
𝑥
< 3.16.0
CNA
Common Weakness Enumeration
References
https://github.com/python/cpython/issues/161707
https://github.com/python/cpython/pull/161711
https://mail.python.org/archives/list/security-announce@python.org/thread/IZL4QUFV7PKGT2JYSU2DCBMLTWYJDGKZ/