openssh: Observable discrepancy leading to an information leak in the algorithm negotiation

The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client). NOTE: some reports state that 8.5 and 8.6 are also affected.

kernel: broken permission and object lifetime handling for PTRACE_TRACEME

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.

Out-of-bounds write in the BIOS firmware for some Intel(R) Processors may allow an authenticated user to potentially enable escalation of privilege via local access.

kernel: new DNS Cache Poisoning Attack based on ICMP fragment needed packets replies

A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypass the source port UDP randomization. The highest threat from this vulnerability is to confidentiality and possibly integrity, because software that relies on UDP source port randomization are indirectly affected as well.

Ubuntu 18.04 Linux kernel i915 incomplete fix for CVE-2019-14615

The fix for the Linux kernel in Ubuntu 18.04 LTS for CVE-2019-14615 ("The Linux kernel did not properly clear data structures on context switches for certain Intel graphics processors.") was discovered to be incomplete, meaning that in versions of the kernel before 4.15.0-91.92, an attacker could use this vulnerability to expose sensitive information.

NetApp AFF A700s Baseboard Management Controller (BMC) firmware versions 1.22 and higher were shipped with a default account enabled that could allow unauthorized arbitrary command execution.

kernel: use-after-free in the XFRM subsystem related to an xfrm_state_fini() panic

An issue was discovered in the Linux kernel before 5.0.19. The XFRM subsystem has a use-after-free, related to an xfrm_state_fini panic, aka CID-dbb2483b2a46.

kernel: out-of-bounds write in __btrfs_map_block in fs/btrfs/volumes.c

In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image and performing some operations can cause slab-out-of-bounds write access in __btrfs_map_block in fs/btrfs/volumes.c, because a value of 1 for the number of data stripes is mishandled.

kernel: use-after-free in __mutex_lock in kernel/locking/mutex.c

In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in __mutex_lock in kernel/locking/mutex.c. This is related to mutex_can_spin_on_owner in kernel/locking/mutex.c, __btrfs_qgroup_free_meta in fs/btrfs/qgroup.c, and btrfs_insert_delayed_items in fs/btrfs/delayed-inode.c.

kernel: use-after-free in rwsem_down_write_slowpath in kernel/locking/rwsem.c

In the Linux kernel 5.3.11, mounting a crafted btrfs image twice can cause an rwsem_down_write_slowpath use-after-free because (in rwsem_can_spin_on_owner in kernel/locking/rwsem.c) rwsem_owner_flags returns an already freed pointer,

kernel: A memory leak in the fastrpc_dma_buf_attach() function in drivers/misc/fastrpc.c allows for a DoS

A memory leak in the fastrpc_dma_buf_attach() function in drivers/misc/fastrpc.c in the Linux kernel before 5.3.9 allows attackers to cause a denial of service (memory consumption) by triggering dma_get_sgtable() failures, aka CID-fc739a058d99.

kernel: dos in crypto_reportstat() function in crypto/crypto_user_stat.c

A memory leak in the crypto_reportstat() function in crypto/crypto_user_stat.c in the Linux kernel through 5.3.11 allows attackers to cause a denial of service (memory consumption) by triggering crypto_reportstat_alg() failures, aka CID-c03b04dcdba1.

kernel: integer overflow in tcp_ack_update_rtt in net/ipv4/tcp_input.c

An issue was discovered in net/ipv4/sysctl_net_ipv4.c in the Linux kernel before 5.0.11. There is a net/ipv4/tcp_input.c signed integer overflow in tcp_ack_update_rtt() when userspace writes a very large integer to /proc/sys/net/ipv4/tcp_min_rtt_wlen, leading to a denial of service or possibly unspecified other impact, aka CID-19fad20d15a6.

kernel: Memory leak in hsr_dev_finalize() in net/hsr/hsr_device.c

In the Linux kernel before 5.0.3, a memory leak exits in hsr_dev_finalize() in net/hsr/hsr_device.c if hsr_add_port fails to add a port, which may cause denial of service, aka CID-6caabe7f197d.

kernel: denial of service in in xfs_setattr_nonsize in fs/xfs/xfs_iops.c

An issue was discovered in xfs_setattr_nonsize in fs/xfs/xfs_iops.c in the Linux kernel through 5.2.9. XFS partially wedges when a chgrp fails on account of being out of disk quota. xfs_setattr_nonsize is failing to unlock the ILOCK after the xfs_qm_vop_chown_reserve call fails. This is primarily a local DoS attack vector, but it might result as well in remote DoS if the XFS filesystem is exported for instance via NFS.

kernel: vhost-net: guest to host kernel escape during migration

A buffer overflow flaw was found, in versions from 2.6.34 to 5.2.x, in the way Linux kernel's vhost functionality that translates virtqueue buffers to IOVs, logged the buffer descriptors during migration. A privileged guest user able to pass descriptors with invalid length to the host when migration is underway, could use this flaw to increase their privileges on the host.

Kernel: KVM: OOB memory access via mmio ring buffer

An out-of-bounds access issue was found in the Linux kernel, all versions through 5.3, in the way Linux kernel's KVM hypervisor implements the Coalesced MMIO write operation. It operates on an MMIO ring buffer 'struct kvm_coalesced_mmio' object, wherein write indices 'ring->first' and 'ring->last' value could be supplied by a host user-space process. An unprivileged host user or process with access to '/dev/kvm' device could use this flaw to crash the host kernel, resulting in a denial of service or potentially escalating privileges on the system.

kernel: null pointer dereference in get_vdev_port_node_info in arch /sparc/kernel/mdesc.c

An issue was discovered in get_vdev_port_node_info in arch/sparc/kernel/mdesc.c in the Linux kernel through 5.1.6. There is an unchecked kstrdup_const of node_info->vdev_port.name, which might allow an attacker to cause a denial of service (NULL pointer dereference and system crash).