Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newline characters into a spool file (which indirectly leads to remote code execution as root) via AUTH= in a MAIL FROM command.
https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28021-MAUTH.txt
Source: MITRE
Published: 2021-05-06
Updated: 2021-05-10
Type: NVD-CWE-Other
Base Score: 9
Vector: AV:N/AC:L/Au:S/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 8
Severity: HIGH
Base Score: 8.8
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 2.8
Severity: HIGH