CVE-2019-3570

Call to the scrypt_enc() function in HHVM can lead to heap corruption by
using specifically crafted parameters (N, r and p). This happens if the
parameters are configurable by an attacker for instance by providing the
output of scrypt_enc() in a context where Hack/PHP code would attempt to
verify it by re-running scrypt_enc() with the same parameters. This could
result in information disclosure, memory being overwriten or crashes of the
HHVM process. This issue affects versions 4.3.0, 4.4.0, 4.5.0, 4.6.0,
4.7.0, 4.8.0, versions 3.30.5 and below, and all versions in the 4.0, 4.1,
and 4.2 series.