cve/2023/CVE-2023-51766.md

### [CVE-2023-51766](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-51766)
![](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

Exim before 4.97.1 allows SMTP smuggling in certain PIPELINING/CHUNKING 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 Exim supports <LF>.<CR><LF> but some other popular e-mail servers do not.

### POC

#### Reference
- https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/

#### Github
- https://github.com/fkie-cad/nvd-json-data-feeds
- https://github.com/hannob/smtpsmug