Information disclosure in Exim

Published: 2016-12-20 | Updated: 2016-12-25
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2016-9963
Exploitation vector Network
Public exploit N/A
Vulnerable software
Server applications / Mail servers

Vendor Exim

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Information disclosure


Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2016-9963

CWE-ID: CWE-200 - Information exposure

Exploit availability: No


The vulnerability allows a remote attacker to obtain potentially sensitive information.

The vulnerability exists due to usage of incorrect buffer when displaying error message for DATA command in src/src/transports/smtp.c file. A remote unauthenticated attacker can send a specially crafted SMTP command and obtain potentially sensitive information, such as DKIM key.


Install the latest version 4.87.1 or 4.88, which fixes this vulnerability.

Vulnerable software versions

Exim: 4.69 - 4.87

External links

Q & A

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.