An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited.

Variant CVE-2017-5753 triggers the speculative execution by performing a bounds-check bypass. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to cross the syscall boundary and read privileged memory by conducting targeted cache side-channel attacks.

The /usr/sbin/pinger binary packaged with squid in SUSE Linux Enterprise Server 15 before and including version 4.8-5.8.1 and in SUSE Linux Enterprise Server 12 before and including 3.5.21-26.17.1 had squid:root, 0750 permissions. This allowed an attacker that compromissed the squid user to gain persistence by changing the binary

An issue was discovered in modaliasphysicalhandler in modalias.c in lighttpd before 1.4.50. There is potential ../ path traversal of a single directory above an alias target, with a specific modalias configuration where the matched alias lacks a trailing '/' character, but the alias target filesystem path does have a trailing '/' character.