[3.9] gh-121284: Fix email address header folding with parsed encoded-word (GH-122754)#131412
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…ncoded-word (pythonGH-122754) Email generators using email.policy.default may convert an RFC 2047 encoded-word to unencoded form during header refolding. In a structured header, this could allow 'specials' chars outside a quoted-string, leading to invalid address headers and enabling spoofing. This change ensures a parsed encoded-word that contains specials is kept as an encoded-word while the header is refolded. [Better fix from @bitdancer.] --------- (cherry picked from commit 295b53d) Co-authored-by: Mike Edmunds <medmunds@gmail.com> Co-authored-by: R David Murray <rdmurray@bitdance.com> Co-authored-by: Petr Viktorin <encukou@gmail.com>
bedevere-appbot added topic-email type-security 
bitdancer approved these changes Mar 18, 2025
ambv merged commit 9a31386 into python:3.9 14 checks passed
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gentoo-bot pushed a commit to gentoo/cpython that referenced this pull request Apr 9, 2025
…ncoded-word (pythonGH-122754) (pythonGH-131412) Email generators using email.policy.default may convert an RFC 2047 encoded-word to unencoded form during header refolding. In a structured header, this could allow 'specials' chars outside a quoted-string, leading to invalid address headers and enabling spoofing. This change ensures a parsed encoded-word that contains specials is kept as an encoded-word while the header is refolded. [Better fix from @bitdancer.] (cherry picked from commit 295b53d) Co-authored-by: Mike Edmunds <medmunds@gmail.com> Co-authored-by: R David Murray <rdmurray@bitdance.com>
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Email generators using email.policy.default may convert an RFC 2047 encoded-word to unencoded form during header refolding. In a structured header, this could allow 'specials' chars outside a quoted-string, leading to invalid address headers and enabling spoofing. This change ensures a parsed encoded-word that contains specials is kept as an encoded-word while the header is refolded.
[Better fix from @bitdancer.]
(cherry picked from commit 295b53d)