Incomplete control character validation in http.cookies
Summary
| CVE | CVE-2026-3644 |
|---|---|
| State | PUBLISHED |
| Assigner | PSF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-16 18:16:09 UTC |
| Updated | 2026-06-30 16:16:50 UTC |
| 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(). |
Risk And Classification
Primary CVSS: v4.0 6 MEDIUM from [email protected]
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
Problem Types: CWE-20 | CWE-116 | CWE-20 CWE-20 Improper Input Validation | CWE-116 CWE-116 Improper Encoding or Escaping of Output
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 6 | MEDIUM | 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/C... |
| 4.0 | CNA | CVSS | 6 | MEDIUM | 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 |
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
LowUser Interaction
NoneConfidentiality
LowIntegrity
HighAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Python Software Foundation | CPython | affected 3.13.13 python | Not specified |
| CNA | Python Software Foundation | CPython | affected 3.14.0 3.14.4 python | Not specified |
| CNA | Python Software Foundation | CPython | affected 3.15.0a1 3.15.0a8 python | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mail.python.org/archives/list/[email protected]/thread/H6CADMBCDRF... | [email protected] | mail.python.org | Third Party Advisory |
| github.com/python/cpython/issues/145599 | [email protected] | github.com | Issue Tracking |
| github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd | [email protected] | github.com | Patch |
| github.com/python/cpython/commit/dae4b1a21f8df4570e30986affd61bbe4ade4cef | [email protected] | github.com | |
| github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd | [email protected] | github.com | Patch |
| github.com/python/cpython/commit/556aa098e738b127c714866f819b4abe2f7593d8 | [email protected] | github.com | |
| github.com/python/cpython/pull/145600 | [email protected] | github.com | Patch |
| github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4 | [email protected] | github.com | Patch |
| 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: Stan Ulbrych (en)
CNA: Stan Ulbrych (en)
CNA: Victor Stinner (en)
CNA: Seth Larson (en)
CNA: Vyom Yadav (en)
There are currently no legacy QID mappings associated with this CVE.