On Wednesday, September 4, 2019, Exim maintainers announced that they received a report of a potential remote exploit in Exim in versions up to and including 4.92.1.
As of Friday, September 6, 2019, Exim has published a fix for CVE-2019-15846.
We will continue to update this page as more information becomes available.
According to Exim development:
If your Exim server accepts TLS connections, it is vulnerable. This does not depend on the TLS libray, so both, GnuTLS and OpenSSL are affected.
The vulnerability is exploitable by sending a SNI ending in a backslash-null sequence during the initial TLS handshake.
The following versions of cPanel & WHM were patched to have the correct version of Exim.
All previous versions of cPanel & WHM below the stated versions are potentially vulnerable to a root RCE.
How to determine if your server is up to date
The updated RPMs provided by cPanel should be at least 4.92-3 on version 82 as well as the EDGE tier, and 4.92-5 on LTS version 78.
Expected response on version 82 and the EDGE tier:
Expected response on LTS version 78:
What to do if you are not up to date.
If your server is not running one of the above versions, update immediately.
To upgrade your server, use WHM's interface (WHM >> Home >> cPanel >> Upgrade to Latest Version).
Alternatively, you can run the commands below to upgrade your server from the command line:
Verify the new Exim RPM was installed:
Run the following:
The output on version 82 and the EDGE tier should resemble below:
The output on LTS version 78 should resemble below:
Run the following to ensure the CVE is in the changelog:
The output on LTS version 78, version 82, and the EDGE tier should resemble below:
More detailed information can be found at the following websites: