cve/2023/CVE-2023-51764.md

### [CVE-2023-51764](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-51764)
![](https://img.shields.io/static/v1?label=Product&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=brighgreen)

### Description

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.

### POC

#### Reference
- https://github.com/duy-31/CVE-2023-51764
- https://github.com/eeenvik1/CVE-2023-51764
- https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/

#### Github
- https://github.com/Double-q1015/CVE-2023-51764
- https://github.com/d4op/CVE-2023-51764-POC
- https://github.com/duy-31/CVE-2023-51764
- https://github.com/eeenvik1/CVE-2023-51764
- https://github.com/fkie-cad/nvd-json-data-feeds
- https://github.com/hannob/smtpsmug
- https://github.com/nomi-sec/PoC-in-GitHub