CVE Vulnerabilities

CVE-2021-38371

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Published: Aug 10, 2021 | Modified: Jun 17, 2026
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu
LOW

The STARTTLS feature in Exim through 4.94.2 allows response injection (buffering) during MTA SMTP sending.

Weakness

The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.

Affected Software

NameVendorStart VersionEnd Version
EximExim*4.94.2 (including)
Exim4Ubuntubionic*
Exim4Ubuntuesm-infra-legacy/trusty*
Exim4Ubuntuesm-infra-legacy/xenial*
Exim4Ubuntuesm-infra/bionic*
Exim4Ubuntuesm-infra/focal*
Exim4Ubuntuesm-infra/xenial*
Exim4Ubuntufocal*
Exim4Ubuntuhirsute*
Exim4Ubuntuimpish*
Exim4Ubuntutrusty*
Exim4Ubuntutrusty/esm*
Exim4Ubuntuupstream*
Exim4Ubuntuxenial*

Potential Mitigations

References