CVE-2020-28018 Use after free in n/a
A use-after-free vulnerability in Exim's smtp_reset function allows attackers to potentially execute arbitrary code or cause a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-28018?
CVE-2020-28018 is a critical use after free 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 allows Use After Free in smtp_reset in certain situations that may be common for builds with OpenSSL.
Weakness: CWE-416
Which versions are affected by CVE-2020-28018?
It affects 1 product.
Products include Exim Exim.
How do I fix CVE-2020-28018?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2020-28018 being exploited?
There is no known exploitation of CVE-2020-28018 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Exim Exim
Sources
Also known as CLEANSTART-2025-XY17493, DEBIAN-CVE-2020-28018, GHSA-5hqr-vx33-mfmh, UBUNTU-CVE-2020-28018.