Command Injection in Exim - CVE-2023-51766

Vulnerability identifier: #VU84728

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2023-51766

CWE-ID: CWE-77

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to spoof email messages.

The vulnerability exists due to an error when handling line endings other than <CR><LF>. A remote attacker can spoof contents of email message and bypass SPF protection mechanism.

Exim
Amazon Linux AMI
Debian Linux
Gentoo Linux
Fedora
Ubuntu
openEuler
eximon4 (Ubuntu package)
exim4-base (Ubuntu package)
exim4 (Ubuntu package)
exim
exim4 (Debian package)
exim-debuginfo
exim-mysql
exim-mon
exim-greylist
exim-pgsql
exim-clamav
exim-debugsource
mail-mta/exim

Install update from vendor's website.

Exim - update to 4.97.1
eximon4 (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.10, 4.95-4ubuntu2.5, 4.96-17ubuntu2.2
exim4-base (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.10, 4.95-4ubuntu2.5, 4.96-17ubuntu2.2
exim4 (Ubuntu package) - addressed in versions Ubuntu Pro, 4.82-3ubuntu2.4+esm9, 4.86.2-2ubuntu2.6+esm9, 4.90.1-1ubuntu1.10+esm6, 4.93-13ubuntu1.10, 4.93-13ubuntu1.12+esm1, 4.95-4ubuntu2.5, 4.96-17ubuntu2.2
exim - update to 4.92-1.40
exim4 (Debian package) - addressed in versions 4.94.2-7+deb11u2, 4.96-15+deb12u4
exim-debuginfo - addressed in versions 4.96-3, 4.97.1-2
exim-mysql - addressed in versions 4.96-3, 4.97.1-2
exim-mon - addressed in versions 4.96-3, 4.97.1-2
exim-greylist - addressed in versions 4.96-3, 4.97.1-2
exim-pgsql - addressed in versions 4.96-3, 4.97.1-2
exim-clamav - addressed in versions 4.96-3, 4.97.1-2
exim-debugsource - addressed in versions 4.96-3, 4.97.1-2
exim - addressed in versions 4.96-3, 4.97.1-2
mail-mta/exim - update to 4.97.1
exim - addressed in versions 4.97.1-1.el7, 4.97.1-1.el8, 4.97.1-1.el9, 4.97.1-1.fc38, 4.97.1-1.fc39

• https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/
• https://exim.org/static/doc/security/CVE-2023-51766.txt
• https://bugs.exim.org/show_bug.cgi?id=3063
• https://www.openwall.com/lists/oss-security/2023/12/23/2
• http://www.openwall.com/lists/oss-security/2023/12/24/1

• SMTP smuggling attack in Exim
• Fedora 39 update for exim
• Fedora 38 update for exim
• Fedora EPEL 9 update for exim
• Fedora EPEL 7 update for exim
• Fedora EPEL 8 update for exim
• Amazon Linux AMI update for exim
• Ubuntu update for exim4
• Gentoo update for Exim
• Debian update for exim4
• openEuler 22.03 LTS SP3 update for exim
• openEuler 22.03 LTS SP4 update for exim
• openEuler 24.03 LTS update for exim
• Ubuntu update for exim4