What’s Vulnerable › Vulnerabilities

CVE-2020-28021

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-05-06 · updated 2026-06-17

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.

Affected products

• Exim: from 4.00 before 4.94.2 — fixed in 4.94.2

How to fix

Upgrade to a fixed version: Exim 4.94.2. Check the vendor advisory for mitigations.

References

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

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