A new domain bypass transient execution attack known as Special Register Buffer Data Sampling (SRBDS) has been found. This flaw allows data values from special internal registers to be leaked by an attacker able to execute code on any core of the CPU. An unprivileged, local attacker can use this flaw to infer values returned by affected instructions known to be commonly used during cryptographic operations that rely on uniqueness, secrecy, or both.

An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions past bounds check.

It relies on the presence of a precisely-defined instruction sequence in the privileged code and the fact that memory writes occur to an address which depends on the untrusted value. Such writes cause an update 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 influence speculative execution and/or read privileged memory by conducting targeted cache side-channel attacks.

Improper data forwarding in some data cache for some Intel(R) Processors may allow an authenticated user to potentially enable information disclosure via local access. The list of affected products is provided in intel-sa-00330: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00330.html

Load value injection in some Intel(R) Processors utilizing speculative execution may allow an authenticated user to potentially enable information disclosure via a side channel with local access. The list of affected products is provided in intel-sa-00334: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00334.html

Unchecked return value in the firmware for some Intel(R) Processors may allow a privileged user to potentially enable an escalation of privilege via local access.

Insecure default variable initialization for the Intel BSSA DFT feature may allow a privileged user to potentially enable an escalation of privilege via local access.