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Actively exploited · Published Feb 8, 2018 · Assigned by mitre

CVE-2018-6789

Critical 9.8 Exploited Ransomware

In plain English

A critical-severity buffer overflow in Exim from Exim. Attackers are actively exploiting it in the wild (listed by CISA on November 3, 2021). It has been used in ransomware campaigns. The chance it is exploited in the next 30 days is estimated at 82.1% (higher than 99.7% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)82.1%top 0.3% of all CVEs
Exploited in the wildYesCISA KEV since Nov 3, 2021
Attack tooling1Public PoC

CISA guidance

Apply updates per vendor instructions.

Federal agencies must remediate by May 3, 2022.

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20exim4.90.1-r0ALPINE-CVE-2018-6789
Alpine:v3.21exim4.90.1-r0ALPINE-CVE-2018-6789
Alpine:v3.22exim4.90.1-r0ALPINE-CVE-2018-6789
Alpine:v3.23exim4.90.1-r0ALPINE-CVE-2018-6789
Alpine:v3.24exim4.90.1-r0ALPINE-CVE-2018-6789
Debian:12exim44.90.1-1DEBIAN-CVE-2018-6789
Debian:13exim44.90.1-1DEBIAN-CVE-2018-6789
Debian:14exim44.90.1-1DEBIAN-CVE-2018-6789

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

Weakness: CWE-120 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References