Integer overflow in Exim - CVE-2020-28017

Vulnerability identifier: #VU52863

CSH Severity: High

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-2020-28017

CWE-ID: CWE-190

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 integer overflow within the receive_add_recipient() function. A remote attacker can pass specially crafted data to the application, trigger integer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Exim
Gentoo Linux
Amazon Linux AMI
Ubuntu
exim4 (Debian package)
exim4-base (Ubuntu package)
exim4-daemon-heavy (Ubuntu package)
exim4-daemon-light (Ubuntu package)

Install updates from vendor's website.

Exim - update to 4.94.2
exim4 (Debian package) - update to 4.92-8+deb10u6
exim4-base (Ubuntu package) - addressed in versions 4.86.22ubuntu2.6+esm1, 4.90.1-1ubuntu1.8, 4.93-13ubuntu1.5, 4.94-7ubuntu1.2, 4.94-15ubuntu1.2
exim4-daemon-heavy (Ubuntu package) - addressed in versions 4.86.22ubuntu2.6+esm1, 4.90.1-1ubuntu1.8, 4.93-13ubuntu1.5, 4.94-7ubuntu1.2, 4.94-15ubuntu1.2
exim4-daemon-light (Ubuntu package) - addressed in versions 4.86.22ubuntu2.6+esm1, 4.90.1-1ubuntu1.8, 4.93-13ubuntu1.5, 4.94-7ubuntu1.2, 4.94-15ubuntu1.2

• http://seclists.org/oss-sec/2021/q2/91

• Multiple vulnerabilities in Exim
• Gentoo update for Exim
• Debian update for exim4
• Amazon Linux AMI update for exim
• Ubuntu update for exim4
• Ubuntu update for exim4