Postfix 2.1.3, when /proc/net/if_inet6 is not available and permit_mx_backup is enabled in smtpd_recipient_restrictions, allows remote attackers to bypass e-mail restrictions and perform mail relaying by sending mail to an IPv6 hostname.

Vulnerability in Postfix SMTP server before 20010228-pl07, when configured to email the postmaster when SMTP errors cause the session to terminate, allows remote attackers to cause a denial of service (memory exhaustion) by generating a large number of SMTP errors, which forces the SMTP session log to grow too large.

Multiple SQL injection vulnerabilities in Postfix Admin (aka postfixadmin) before 2.3.5 allow remote authenticated users to execute arbitrary SQL commands via (1) the pw parameter to the pacrypt function, when mysql_encrypt is configured, or (2) unspecified vectors that are used in backup files generated by backup.php.

Postfix 2.5 before 2.5.4 and 2.6 before 2.6-20080814 delivers to a mailbox file even when this file is not owned by the recipient, which allows local users to read e-mail messages by creating a mailbox file corresponding to another user's account name.

The STARTTLS implementation in Postfix 2.4.x before 2.4.16, 2.5.x before 2.5.12, 2.6.x before 2.6.9, and 2.7.x before 2.7.3 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted SMTP sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack.

** DISPUTED ** postfix_groups.pl in Postfix 2.5.2 allows local users to overwrite arbitrary files via a symlink attack on the (1) /tmp/postfix_groups.stdout, (2) /tmp/postfix_groups.stderr, and (3) /tmp/postfix_groups.message temporary files. NOTE: the vendor disputes this vulnerability, stating "This is not a real issue ... users would have to edit a script under /usr/lib to enable it."

ELSA-2026-26205: postfix security update (IMPORTANT)

ELSA-2026-25932: postfix security update (IMPORTANT)

ELSA-2026-25930: postfix security update (IMPORTANT)

ELSA-2024-9243: postfix security update (MODERATE)

ELSA-2011-0843: postfix security update (MODERATE)

ELSA-2011-0423: postfix security update (MODERATE)

ELSA-2008-0839: postfix security update (MODERATE)

Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.

Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.

Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 sometimes allows a buffer over-read and process crash via an enhanced status code that lacks text after the third number.

Postfix before 3.8.16, 3.9 before 3.9.10, and 3.10 before 3.10.9 somet ...

Postfix through 3.8.5 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, such as 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.

Postfix through 3.8.5 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, such as 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.

Postfix through 3.8.5 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, such as 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.