vulnerability
Ubuntu: (Multiple Advisories) (CVE-2023-51766): Exim vulnerability
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 5 | (AV:N/AC:L/Au:N/C:N/I:P/A:N) | Dec 24, 2023 | Jan 31, 2024 | Jun 4, 2026 |
Severity
5
CVSS
(AV:N/AC:L/Au:N/C:N/I:P/A:N)
Published
Dec 24, 2023
Added
Jan 31, 2024
Modified
Jun 4, 2026
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.
Solutions
ubuntu-pro-upgrade-exim4ubuntu-pro-upgrade-exim4-baseubuntu-pro-upgrade-exim4-daemon-heavyubuntu-pro-upgrade-exim4-daemon-lightubuntu-pro-upgrade-exim4-devubuntu-pro-upgrade-eximon4ubuntu-upgrade-exim4ubuntu-upgrade-exim4-baseubuntu-upgrade-eximon4
Rapid7 Labs
2026 Global Threat Landscape Report
The predictive window has collapsed. Exploitation follows disclosure in days. See how attackers are accelerating and how to stay ahead.