9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
0.968 High
EPSS
Percentile
99.6%
Added: 05/16/2018
CVE: CVE-2018-6789
BID: 103049
Exim is a mail transfer agent used on Unix-like operating systems.
Exim 5.90 and earlier are vulnerable to a one-character buffer overflow in the **base64d()**
function in the SMTP listener.
Upgrade to Exim 4.90.1 or higher, apply the update from your system vendor, or apply the patch supplied by Exim.
<https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/>
<https://exim.org/static/doc/security/CVE-2018-6789.txt>
<https://bugzilla.redhat.com/show_bug.cgi?id=1543268>
<https://bugzilla.novell.com/show_bug.cgi?id=1079832>
Exploit works on Exim 4.89 and 4.88 on Debian stretch and Ubuntu zesty.
The target Exim configuration must have an authenticator using base64 enabled. CRAM-MD5 authenticator uses base64 and is enabled by default.
Linux
9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
0.968 High
EPSS
Percentile
99.6%