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().
Affected products
python: python
References9
- github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010… Patch
- github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f… Patch
- github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c839… Patch
- github.com/python/cpython/pull/145600 Patch
- github.com/python/cpython/commit/3974092b037f9a3b000fb15b48ea61…
- github.com/python/cpython/commit/556aa098e738b127c714866f819b4a…
- github.com/python/cpython/commit/dae4b1a21f8df4570e30986affd61b…
- github.com/python/cpython/issues/145599 Issue Tracking
- mail.python.org/archives/list/[email protected]/thre… Third Party Advisory
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 4.0
-
6.0
MEDIUM
Score source: CNA
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 - EPSS — exploit probability
- 1% percentile: 46 · as of 12 November 2026
- CWE
- CWE-20CWE-116
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.