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CVE-2026-3644

Incomplete control character validation in http.cookies

Published: Mar 16, 2026Updated: Jun 4, 2026 Sources: CVE List NVD BDUCWE-20
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.4%
Top 69.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-20CWE-116

Affected Products

CPythonPython Software FoundationOSS Libraries
pythonpythonOSS Libraries
Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
РЕД ОСООО «Ред Софт»
On-premOS
Operating Systems / linux-distro
python software foundationoss-projectUSOSS Librariesaka python software foundation, psf
pythonoss-projectUSOSS Libraries
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
ооо «ред софт»commercialRUOperating Systemsaka red soft

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
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References

https://mail.python.org/archives/list/security-announce@python.org/thread/H6CADMBCDRFGWCMOXWUIHFJNV43GABJ7/
mail.python.org
https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4
github.com
https://github.com/python/cpython/issues/145599
github.com
and 10 more references View all →

Timeline

Published
Mar 16, 2026
Last Updated
Jun 4, 2026

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