Wi-Fi Protected Access (WPA and WPA2) allows re-installation of the Group Temporal Key (GTK) during the group key handshake, allowing an attacker within radio range to replay frames from access points to clients. Jann Horn discovered that the Berkeley Packet Filter (BPF) implementation in the Linux kernel improperly performed sign extension in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.
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