HylaFAX 6.0.6 and HylaFAX+ 5.6.0 allow remote attackers to execute arbitrary code via a dial-in session that provides a FAX page with the JPEG bit enabled, which is mishandled in FaxModem::writeECMData() in the faxd/CopyQuality.c++ file.
git.hylafax.org/HylaFAX?a=commit%3Bh=c6cac8d8cd0dbe313689ba77023e12bc5b3027be
www.openwall.com/lists/oss-security/2018/09/20/1
lists.debian.org/debian-lts-announce/2018/09/msg00026.html
seclists.org/bugtraq/2018/Sep/49
www.debian.org/security/2018/dsa-4298
www.x41-dsec.de/lab/advisories/x41-2018-008-hylafax/