arch/arm64/kvm/guest.c in KVM in the Linux kernel before 4.18.12 on the arm64 platform mishandles the KVM_SET_ON_REG ioctl. This is exploitable by attackers who can create virtual machines. An attacker can arbitrarily redirect the hypervisor flow of control (with full register control). An attacker can also cause a denial of service (hypervisor panic) via an illegal exception return. This occurs because of insufficient restrictions on userspace access to the core register file, and because PSTATE.M validation does not prevent unintended execution modes.

An issue was discovered in the proc_pid_stack function in fs/proc/base.c in the Linux kernel through 4.18.11. It does not ensure that only root may inspect the kernel stack of an arbitrary task, allowing a local attacker to exploit racy stack unwinding and leak kernel task stack contents.

A security flaw was found in the chap_server_compute_md5() function in the ISCSI target code in the Linux kernel in a way an authentication request from an ISCSI initiator is processed. An unauthenticated remote attacker can cause a stack buffer overflow and smash up to 17 bytes of the stack. The attack requires the iSCSI target to be enabled on the victim host. Depending on how the target's code was built (i.e. depending on a compiler, compile flags and hardware architecture) an attack may lead to a system crash and thus to a denial-of-service or possibly to a non-authorized access to data exported by an iSCSI target. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is highly unlikely. Kernel versions 4.18.x, 4.14.x and 3.10.x are believed to be vulnerable.

An issue was discovered in the Linux kernel through 4.18.8. The vmacache_flush_all function in mm/vmacache.c mishandles sequence number overflows. An attacker can trigger a use-after-free (and possibly gain privileges) via certain thread creation, map, unmap, invalidation, and dereference operations.

A flaw was found in the way Linux kernel KVM hypervisor before 4.18 emulated instructions such as sgdt/sidt/fxsave/fxrstor. It did not check current privilege(CPL) level while emulating unprivileged instructions. An unprivileged guest user/process could use this flaw to potentially escalate privileges inside guest.

An issue was discovered in the Linux kernel before 4.18.6. An information leak in cdrom_ioctl_drive_status in drivers/cdrom/cdrom.c could be used by local attackers to read kernel memory because a cast from unsigned long to int interferes with bounds checking. This is similar to CVE-2018-10940.

The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments. Various vulnerabilities in IP fragmentation have been discovered and fixed over the years. The current vulnerability (CVE-2018-5391) became exploitable in the Linux kernel with the increase of the IP fragment reassembly queue size.

An issue was discovered in yurex_read in drivers/usb/misc/yurex.c in the Linux kernel before 4.17.7. Local attackers could use user access read/writes with incorrect bounds checking in the yurex USB driver to crash the kernel or potentially escalate privileges.

arch/x86/kernel/paravirt.c in the Linux kernel before 4.18.1 mishandles certain indirect calls, which makes it easier for attackers to conduct Spectre-v2 attacks against paravirtual guests.

The spectre_v2_select_mitigation function in arch/x86/kernel/cpu/bugs.c in the Linux kernel before 4.18.1 does not always fill RSB upon a context switch, which makes it easier for attackers to conduct userspace-userspace spectreRSB attacks.

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks.

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.

drivers/infiniband/core/ucma.c in the Linux kernel through 4.17.11 allows ucma_leave_multicast to access a certain data structure after a cleanup step in ucma_process_join, which allows attackers to cause a denial of service (use-after-free).

An issue was discovered in the Linux kernel through 4.17.11, as used in Xen through 4.11.x. The xen_failsafe_callback entry point in arch/x86/entry/entry_64.S does not properly maintain RBX, which allows local users to cause a denial of service (uninitialized memory usage and system crash). Within Xen, 64-bit x86 PV Linux guest OS users can trigger a guest OS crash or possibly gain privileges.

An issue was discovered in the Linux kernel through 4.17.10. There is a NULL pointer dereference and panic in hfsplus_lookup() in fs/hfsplus/dir.c when opening a file (that is purportedly a hard link) in an hfs+ filesystem that has malformed catalog data, and is mounted read-only without a metadata directory.

An issue was discovered in the Linux kernel through 4.17.10. There is a NULL pointer dereference in fscrypt_do_page_crypto() in fs/crypto/crypto.c when operating on a file in a corrupted f2fs image.

An issue was discovered in the Linux kernel through 4.17.10. There is a buffer overflow in truncate_inline_inode() in fs/f2fs/inline.c when umounting an f2fs image, because a length value may be negative.

An issue was discovered in the Linux kernel through 4.17.10. There is an out-of-bounds access in __remove_dirty_segment() in fs/f2fs/segment.c when mounting an f2fs image.

An issue was discovered in the Linux kernel through 4.17.10. There is an invalid pointer dereference in io_ctl_map_page() when mounting and operating a crafted btrfs image, because of a lack of block group item validation in check_leaf_item in fs/btrfs/tree-checker.c.

An issue was discovered in the Linux kernel through 4.17.10. There is an invalid pointer dereference in btrfs_root_node() when mounting a crafted btrfs image, because of a lack of chunk block group mapping validation in btrfs_read_block_groups in fs/btrfs/extent-tree.c, and a lack of empty-tree checks in check_leaf in fs/btrfs/tree-checker.c.