Federico Manuel Bento discovered that the Linux kernel did not properly apply Address Space Layout Randomization (ASLR) in some situations for setuid a.out binaries. A local attacker could use this to improve the chances of exploiting an existing vulnerability in a setuid a.out binary.
As a hardening measure, this update disables a.out support.
4.15.0-51.554.15.0-1040.424.15.0-1033.354.15.0-1035.354.15.0-1039.444.15.0-1014.164.15.0-1037.394.15.0-1054.58