SMTP Smuggling Vulnerability in Exim Email Server Software
CVE-2023-51766

5.3MEDIUM

Key Information:

Vendor

Exim

Status
Exim
Vendor
CVE Published:
24 December 2023

What is CVE-2023-51766?

A vulnerability within the Exim mail transfer agent allows remote attackers to exploit insecure configurations involving PIPELINING and CHUNKING techniques. This can enable the injection of email messages with spoofed 'MAIL FROM' addresses, effectively bypassing SPF protection mechanisms. The root cause of this issue lies in Exim's support for specific line termination sequences, which some other email servers do not handle in the same way, presenting a risk for email integrity and authentication.

References

https://sec-consult.com/blog/detail/smtp-smuggling-spoofi...
https://exim.org/static/doc/security/CVE-2023-51766.txt
https://bugs.exim.org/show_bug.cgi?id=3063

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.