A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z3 Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient validation of client-supplied parameters while establishing an SSL VPN session. An attacker could exploit this vulnerability by crafting a malicious request and sending it to the affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to crash and restart, resulting in the failure of the established SSL VPN connections and forcing remote users to initiate a new VPN connection and re-authenticate. A sustained attack could prevent new SSL VPN connections from being established. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention. Cisco Meraki has released software updates that address this vulnerability.

A flaw was found in the Linux kernels wifi implementation. An attacker connected to the wireless network can send 'authentication and key management' frames to any participant on the network. These frames are only intended to be sent from the controlling access point however the kernel did not prevent retransmission of these packets from non-controlling nodes.

Upstream fix: https://lore.kernel.org/linux-wireless/20210511200110.cb327ed0cabe.Ib7dcffa2a31f0913d660de65ba3c8aca75b1d10f@changeid/

A flaw was found in the Linux kernel's wifi implementation wherein an attacker within wireless range is able to abuse a logic flaw in the wifi implementation by reassembling packets from multiple fragments under different keys and they would be treated as valid. This allows an attacker to send a fragment under an incorrect key and be treated as a valid fragment under the new key.

Upstream patch: https://lore.kernel.org/linux-wireless/20210511200110.3f8290e59823.I622a67769ed39257327a362cfc09c812320eb979@changeid/

A flaw was found in the Linux kernels wifi implementation. An attacker within wireless broadcast range can inject custom data into the wireless communication circumventing checks on the data. This can cause the frame to pass checks and be considered a valid frame of a different type.

A vulnerability was found in Linux Kernel. Where the Wifi implementations accept plaintext frames in a protected Wi-Fi network. An adversary can abuse this to inject arbitrary data frames independent of the network configuration.

Upstream patch: https://lore.kernel.org/linux-wireless/20210511180259.159598-1-johannes@sipsolutions.net/

A vulnerability was found in Linux Kernel's Wi-Fi implementation. An attacker within wireless range can inject a control packet fragment where the kernel does not verify the Message Integrity Check (authenticity) of fragmented TKIP frames.

Upstream patch: https://lore.kernel.org/linux-wireless/20210511180259.159598-1-johannes@sipsolutions.net/ https://lore.kernel.org/linux-wireless/20210511200110.c3f1d42c6746.I795593fcaae941c471425b8c7d5f7bb185d29142@changeid/