This security advisory describes one high risk vulnerability.
The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.
The vulnerability exists due to insufficient validation of email address within the deliver_message() function in /src/deliver.c. A remote unauthenticated attacker can send an email containing a specially crafted email address and execute arbitrary OS commands on the target system via execv() call with superuser privileges.
This vulnerability can be also exploited by authenticated local users to escalate privileges on the system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.Mitigation
Install updates from vendor's website.Vulnerable software versions
Exim: 4.87, 4.87.1, 4.88, 4.89, 4.89.1, 4.90, 4.91CPE
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.