CVE-2026-3644

MEDIUM EPSS 31.0%
Published Mar 16, 20263mo ago · Modified Jun 17, 20261w ago
6.0 CVSS 4.0
Medium
Find Similar
Published Mar 16, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

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 Details

Base Score
6.0
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/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
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
31.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 2

CWE-116
CWE-20 Improper Input Validation Validation

Affected Products 9

VendorProductVersionRange
pythonpython* <3.13.13
pythonpython*≥3.14.0  –  <3.14.4
pythonpython3.15.0any
pythonpython3.15.0any
pythonpython3.15.0any
pythonpython3.15.0any
pythonpython3.15.0any
pythonpython3.15.0any
pythonpython3.15.0any

References 6

  • github.com https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4
    Patch
  • github.com https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd
    Patch
  • github.com https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd
    Patch
  • github.com https://github.com/python/cpython/issues/145599
    Issue Tracking
  • github.com https://github.com/python/cpython/pull/145600
    Patch
  • mail.python.org https://mail.python.org/archives/list/security-announce@python.org/thread/H6CADMBCDRFGWCMOXWUIHFJNV43GABJ7/
    Third Party Advisory

Remediation

  • github.com https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4
    Patch
  • github.com https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd
    Patch
  • github.com https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd
    Patch
  • github.com https://github.com/python/cpython/pull/145600
    Patch