CVE-2026-3644
HIGHDescription
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 v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 31% of all known CVEs.
References
- https://github.com/python/cpython/commit/556aa098e738b127c714866f819b4abe2f7593d8
- https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4
- https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd
- https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd
- https://github.com/python/cpython/commit/dae4b1a21f8df4570e30986affd61bbe4ade4cef
- https://github.com/python/cpython/issues/145599
- https://github.com/python/cpython/pull/145600
- https://mail.python.org/archives/list/[email protected]/thread/H6CADMBCDRFGWCMOXWUIHFJNV43GABJ7/
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.