CVE-2020-28026 Command injection in n/a

Critical 9.8 Published 6 May 2021 Updated 4 Aug 2024

Unauthenticated remote attackers can execute arbitrary commands as root via newline injection in DSN headers when enabled.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2020-28026?

CVE-2020-28026 is a critical command injection vulnerability in Exim Exim, published on 6 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters, relevant in non-default configurations that enable Delivery Status Notification (DSN). Certain uses of ORCPT= can place a newline into a spool header file, and indirectly allow unauthenticated remote attackers to execute arbitrary commands as root.

Which versions are affected by CVE-2020-28026?

It affects 1 product.

Products include Exim Exim.

How do I fix CVE-2020-28026?

Upgrade to a fixed version.

Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.

Is CVE-2020-28026 being exploited?

There is no known exploitation of CVE-2020-28026 in the wild and no public exploit code.

All Exim Exim vulnerabilities

Sources

Also known as CLEANSTART-2025-VY34802, DEBIAN-CVE-2020-28026, GHSA-gf8c-vh34-8jv5, UBUNTU-CVE-2020-28026.