The Bluetooth SIG released an errata for the 4.2 and 5.0 versions of Bluetooth specification on July 23rd relating to a potential vulnerability with the pairing procedures.
For Bluetooth low energy; this only impacts the low energy secure connections mode of pairing, or LESC. LESC is using Diffie Helman key exchange and the potential vulnerability has to do with key validation not bein a mandatory feature in the previous releases of the specification.
Nordic Semiconductor is taking security very serious and we already mitigated this attack in the nRF5 SDK release 15 back in March 2018.
For more information please check out our the white paper about this issue on the infocenter