CVE-2018-6789

CRITICAL9.8

CISA KEV

Published 2018-02-08 · Updated 2026-06-17 · Source cve@mitre.org

Summary

CVE-2018-6789 is a critical-severity (CVSS 9.8) vulnerability in Exim Exim. CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by May 3, 2022. CISA also lists it as known to be used in ransomware campaigns, so it should be prioritised accordingly. Exim has 5 vulnerabilities in the KEV catalog, 1 of them linked to ransomware.

All 5 known-exploited Exim vulnerabilities →

Description

An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE-120CWE-120

CISA Known-Exploited Vulnerability

Product: Exim — Exim

Name: Exim Buffer Overflow Vulnerability

Date added: 2021-11-03 · Due: 2022-05-03

USED IN RANSOMWARE

Required action: Apply updates per vendor instructions.

References

View on NVD

More exploited Exim vulnerabilities

Most recently added to CISA KEV

CVE-2010-4345
Exim — Exim Privilege Escalation Vulnerability
added 2022-03-25
CVE-2010-4344
Exim — Exim Heap-Based Buffer Overflow Vulnerability
added 2022-03-25
CVE-2019-16928
Exim Internet Mailer — Exim Out-of-bounds Write Vulnerability
added 2022-03-03
CVE-2019-10149
Mail Transfer Agent (MTA) — Exim Mail Transfer Agent (MTA) Improper Input Validation
added 2022-01-10

View all →

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