Important: postfix

Issue Overview:

Postfix through 3.8.4 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). 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 Postfix supports <LF>.<CR><LF> but some other popular e-mail servers do not. To prevent attack variants (by always disallowing <LF> without <CR>), a different solution is required: the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9. (CVE-2023-51764)

Affected Packages:

postfix

Issue Correction:
Run yum update postfix to update your system.

New Packages:

i686:  
    postfix-debuginfo-2.6.6-2.17.amzn1.i686  
    postfix-2.6.6-2.17.amzn1.i686  
    postfix-perl-scripts-2.6.6-2.17.amzn1.i686  
  
src:  
    postfix-2.6.6-2.17.amzn1.src  
  
x86_64:  
    postfix-2.6.6-2.17.amzn1.x86_64  
    postfix-debuginfo-2.6.6-2.17.amzn1.x86_64  
    postfix-perl-scripts-2.6.6-2.17.amzn1.x86_64  

Additional References

Red Hat: CVE-2023-51764

Mitre: CVE-2023-51764