OpenSSL -- Overflow vulnerability

The OpenSSL project reports:

rsaz_512_sqr overflow bug on x86_64 (CVE-2019-1551) (Low)
There is an overflow bug in the x64_64 Montgomery squaring procedure
used in exponentiation with 512-bit moduli. No EC algorithms are
affected. Analysis suggests that attacks against 2-prime RSA1024,
3-prime RSA1536, and DSA1024 as a result of this defect would be very
difficult to perform and are not believed likely. Attacks against
DH512 are considered just feasible. However, for an attack the target
would have to re-use the DH512 private key, which is not recommended
anyway. Also applications directly using the low level API BN_mod_exp
may be affected if they use BN_FLG_CONSTTIME.