CVE Vulnerabilities

CVE-2023-51766

Insufficient Verification of Data Authenticity

Published: Dec 24, 2023 | Modified: Nov 04, 2025
CVSS 3.x
5.3
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM
root.io logo minimus.io logo echo.ai logo

Exim before 4.97.1 allows SMTP smuggling in certain PIPELINING/CHUNKING configurations. Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Exim supports . but some other popular e-mail servers do not.

Weakness

The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

Affected Software

NameVendorStart VersionEnd Version
EximExim*4.97.1 (excluding)
Exim4Ubuntubionic*
Exim4Ubuntudevel*
Exim4Ubuntuesm-infra/bionic*
Exim4Ubuntuesm-infra/focal*
Exim4Ubuntuesm-infra/xenial*
Exim4Ubuntufocal*
Exim4Ubuntujammy*
Exim4Ubuntulunar*
Exim4Ubuntumantic*
Exim4Ubuntunoble*
Exim4Ubuntuoracular*
Exim4Ubuntuplucky*
Exim4Ubuntuquesting*
Exim4Ubuntutrusty*
Exim4Ubuntutrusty/esm*
Exim4Ubuntuupstream*
Exim4Ubuntuxenial*

References