Incomplete control character validation in http.cookies
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().
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-3644US | high7.5 | — | ||
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, allowi… | ||||
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references
External citations — patches, advisories, analysis.
- https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4WEB
- https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590ddWEB
- https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979ddWEB
- https://github.com/python/cpython/issues/145599WEB
- https://github.com/python/cpython/pull/145600WEB
- https://mail.python.org/archives/list/security-announce@python.org/thread/H6CADMBCDRFGWCMOXWUIHFJNV43GABJ7/WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-3644WEB
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