In Eclipse Mosquitto 1.4.14, if a Mosquitto instance is set running with a configuration file, then sending a HUP signal to server triggers the configuration to be reloaded from disk. If there are lots of clients connected so that there are no more file descriptors/sockets available (default limit typically 1024 file descriptors on Linux), then opening the configuration file will fail.

References

• https://nvd.nist.gov/vuln/detail/CVE-2017-7652
• https://bugs.eclipse.org/bugs/show_bug.cgi?id=530102
• https://lists.debian.org/debian-lts-announce/2018/03/msg00037.html
• https://lists.debian.org/debian-lts-announce/2018/06/msg00016.html
• https://mosquitto.org/blog/2018/02/security-advisory-cve-2017-7651-cve-2017-7652/
• https://www.debian.org/security/2018/dsa-4325