CVE-2020-28024

Published: May 6, 2021Modified: Jun 17, 2026

9.8

Vector

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

Exploitability: 3.9 / Impact: 5.9

Source: NVD

Description

Exim 4 before 4.94.2 allows Buffer Underwrite that may result in unauthenticated remote attackers executing arbitrary commands, because smtp_ungetc was only intended to push back characters, but can actually push back non-character error codes such as EOF.

Affected (1)

Products: Exim: Exim

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Exim Exim	From 4.00 to 4.94.2

Related CWEs

Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

References (2)

https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28024-UNGET.txt

Source: cve@mitre.org

Third Party Advisory

https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28024-UNGET.txt

Source: af854a3a-2127-422b-91ae-364da2661108

Third Party Advisory

Timeline

No history available yet.