Stack-based buffer overflow in Exim - CVE-2023-42116

Vulnerability identifier: #VU81253

CSH Severity: Critical

CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2023-42116

CWE-ID: CWE-121

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when handling NTLM challenge requests. A remote unauthenticated attacker can send specially crafted data to the server, trigger a stack-based buffer overflow and execute arbitrary code on the target system.

Exim
Debian Linux
Gentoo Linux
Amazon Linux AMI
Fedora
Ubuntu
RecoverPoint for Virtual Machines
eximon4 (Ubuntu package)
exim4-daemon-light (Ubuntu package)
exim4-daemon-heavy (Ubuntu package)
exim4-base (Ubuntu package)
exim4 (Ubuntu package)
exim
mail-mta/exim
exim4 (Debian package)

Install update from vendor's website.

Exim - addressed in versions 4.96.1, 4.97
RecoverPoint for Virtual Machines - update to 6.0 SP2 P1
eximon4 (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.8, 4.95-4ubuntu2.3, 4.96-14ubuntu1.2
exim4-daemon-light (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.8, 4.95-4ubuntu2.3, 4.96-14ubuntu1.2
exim4-daemon-heavy (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.8, 4.95-4ubuntu2.3, 4.96-14ubuntu1.2
exim4-base (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.8, 4.95-4ubuntu2.3, 4.96-14ubuntu1.2
exim4 (Ubuntu package) - addressed in versions Ubuntu Pro, 4.93-13ubuntu1.8, 4.95-4ubuntu2.3, 4.96-14ubuntu1.2
exim - update to 4.92-1.39
exim - addressed in versions 4.96.1-1.el7, 4.96.1-1.el8, 4.96.1-1.el9, 4.96.1-1.fc37, 4.96.1-1.fc38, 4.96.1-1.fc39, 4.96.1-1.fc40
mail-mta/exim - update to 4.97.1
exim4 (Debian package) - addressed in versions 4.94.2-7+deb11u1, 4.96-15+deb12u2

• https://www.zerodayinitiative.com/advisories/ZDI-23-1470/
• https://www.exim.org/static/doc/security/CVE-2023-zdi.txt

• Multiple vulnerabilities in Exim
• Fedora 40 update for exim
• Fedora 39 update for exim
• Fedora 38 update for exim
• Fedora 37 update for exim
• Fedora EPEL 9 update for exim
• Fedora EPEL 8 update for exim
• Fedora EPEL 7 update for exim
• Debian update for exim4
• Ubuntu update for exim4
• Amazon Linux AMI update for exim
• Gentoo update for Exim
• Dell RecoverPoint for Virtual Machines update for third-party components