Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. Because Exim operates as root in the log directory (owned by a non-root user), a symlink or hard link attack allows overwriting critical root-owned files anywhere on the filesystem.
https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28007-LFDIR.txt
Source: MITRE
Published: 2021-05-06
Updated: 2021-05-10
Type: CWE-59
Base Score: 7.2
Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 3.9
Severity: HIGH
Base Score: 7.8
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.8
Severity: HIGH