Description
Exim through 4.97.1 misparses a multiline RFC 2231 header filename, and thus remote attackers can bypass a $mime_filename extension-blocking protection mechanism, and potentially deliver executable attachments to the mailboxes of end users.
References
git.exim.org/...mit/6ce5c70cff8989418e05d01fd2a57703007a6357
git.exim.org/...mit/1b3209b0577a9327ebb076f3b32b8a159c253f7b
github.com/Exim/exim/compare/exim-4.98-RC2...exim-4.98-RC3
www.rfc-editor.org/rfc/rfc2231.txt
bugs.exim.org/show_bug.cgi?id=3099
