Debian Security Advisory DSA 4053-1 (exim4 - security update)

Several vulnerabilities have been discovered in Exim, a mail transport agent. The Common Vulnerabilities and Exposures project identifies the following issues: CVE-2017-16943 A use-after-free vulnerability was discovered in Exim's routines responsible for parsing mail headers. A remote attacker can take advantage of this flaw to cause Exim to crash, resulting in a denial of service, or potentially for remote code execution. CVE-2017-16944 It was discovered that Exim does not properly handle BDAT data headers allowing a remote attacker to cause Exim to crash, resulting in a denial of service.

exim4 on Debian Linux

This check tests the installed software version using the apt package manager.

For the stable distribution (stretch), these problems have been fixed in version 4.89-2+deb9u2. Default installations disable advertising the ESMTP CHUNKING extension and are not affected by these issues. We recommend that you upgrade your exim4 packages. For the detailed security status of exim4 please refer to its security tracker page linked in the references.