Oracle Linux: CVE-2019-5489: ELSA-2019-4528: Unbreakable Enterprise kernel security update (IMPORTANT) (Multiple Advisories)

The mincore() implementation in mm/mincore.c in the Linux kernel through 4.19.13 allowed local attackers to observe page cache access patterns of other processes on the same system, potentially allowing sniffing of secret information. (Fixing this affects the output of the fincore program.) Limited remote exploitation may be possible, as demonstrated by latency differences in accessing public files from an Apache HTTP Server.
A new software page cache side channel attack scenario was discovered in operating systems that implement the very common 'page cache' caching mechanism. A malicious user/process could use 'in memory' page-cache knowledge to infer access timings to shared memory and gain knowledge which can be used to reduce effectiveness of cryptographic strength by monitoring algorithmic behavior, infer access patterns of memory to determine code paths taken, and exfiltrate data to a blinded attacker through page-granularity access times as a side-channel.