An issue was discovered in rsn_supp/wpa.c in wpa_supplicant 2.0 through 2.6. Under certain conditions, the integrity of EAPOL-Key messages is not checked, leading to a decryption oracle. An attacker within range of the Access Point and client can abuse the vulnerability to recover sensitive information.
https://www.us-cert.gov/ics/advisories/icsa-19-344-01
https://w1.fi/security/2018-1/unauthenticated-eapol-key-decryption.txt
https://usn.ubuntu.com/3745-1/
https://security.FreeBSD.org/advisories/FreeBSD-SA-18:11.hostapd.asc
https://papers.mathyvanhoef.com/woot2018.pdf
https://lists.debian.org/debian-lts-announce/2018/08/msg00009.html
https://cert-portal.siemens.com/productcert/pdf/ssa-344983.pdf
https://access.redhat.com/errata/RHSA-2018:3107
http://www.securitytracker.com/id/1041438
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00013.html