CVE-2020-28021

Name: CVE-2020-28021
Creator: NVD / NIST
Published: 2021-05-06T13:15:09.64+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 4.06%

Last modified Jun 17, 2026

CVE-2020-28021 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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.. EPSS estimates a 4.06% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

4.06%

89.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Exim	Exim	>= 4.00, < 4.94.2

References

https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28021-MAUTH.txtVendor Advisory
https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28021-MAUTH.txtVendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2020-28021?

How severe is CVE-2020-28021?

CVE-2020-28021 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 4.06% probability of exploitation in the next 30 days.

How do I fix CVE-2020-28021?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-28021?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST