The Bluetooth BR/EDR specification up to and including version 5.1 permits sufficiently low encryption key length and does not prevent an attacker from influencing the key length negotiation. This allows practical brute-force attacks (aka "KNOB") that can decrypt traffic and inject arbitrary ciphertext without the victim noticing.

In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to create a ptrace relationship, which allows local users to obtain root access by leveraging certain scenarios with a parent-child process relationship, where a parent drops privileges and calls execve (potentially allowing control by an attacker). One contributing factor is an object lifetime issue (which can also cause a panic). Another contributing factor is incorrect marking of a ptrace relationship as privileged, which is exploitable through (for example) Polkit's pkexec helper with PTRACE_TRACEME. NOTE: SELinux deny_ptrace might be a usable workaround in some environments.

A flaw was found in the Linux kernel. A heap based buffer overflow in mwifiex_uap_parse_tail_ies function in drivers/net/wireless/marvell/mwifiex/ie.c might lead to memory corruption and possibly other consequences.

fs/ext4/extents.c in the Linux kernel through 5.1.2 does not zero out the unused memory region in the extent tree block, which might allow local users to obtain sensitive information by reading uninitialized data in the filesystem.

The do_hidp_sock_ioctl function in net/bluetooth/hidp/sock.c in the Linux kernel before 5.0.15 allows a local user to obtain potentially sensitive information from kernel stack memory via a HIDPCONNADD command, because a name field may not end with a '\0' character.

A heap address information leak while using L2CAP_GET_CONF_OPT was discovered in the Linux kernel before 5.1-rc1.

A heap data infoleak in multiple locations including L2CAP_PARSE_CONF_RSP was found in the Linux kernel before 5.1-rc1.

A flaw was found in the way KVM hypervisor handled x2APIC Machine Specific Rregister (MSR) access with nested(=1) virtualization enabled. In that, L1 guest could access L0's APIC register values via L2 guest, when 'virtualize x2APIC mode' is enabled. A guest could use this flaw to potentially crash the host kernel resulting in DoS issue. Kernel versions from 4.16 and newer are vulnerable to this issue.

The KVM implementation in the Linux kernel through 4.20.5 has an Information Leak.