CVE-2023-51765

sendmail through 8.17.2 allows SMTP smuggling in certain configurations.
Remote attackers can use a published exploitation technique to inject
e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF
protection mechanism. This occurs because sendmail supports <LF>.<CR><LF>
but some other popular e-mail servers do not. This is resolved in 8.18 and
later versions with ‘o’ in srv_features.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1059386&gt;