Incomplete control character validation in http.cookies

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

Also Affects

Downstream vendors/products affected by this vulnerability

References

• https://mail.python.org/archives/list/security-announce@python.org/thread/H6CADMBCDRFGWCMOXWUIHFJNV43GABJ7/(vendor-advisory)
• https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4(patch)
• https://github.com/python/cpython/issues/145599(issue-tracking)
• https://github.com/python/cpython/pull/145600(patch)
• https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd(patch)
• https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd(patch)

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