known ransomware use

Exim Buffer Overflow Vulnerability

Added to KEV
2021-11-03
Federal due date
2022-05-03
Vendor
Exim
Product
Exim
EPSS
99.4th percentile (score 0.866, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2018-6789

CISA short description

Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.