An issue was discovered in the Linux kernel through 4.17.3. An Integer Overflow in kernel/time/posix-timers.c in the POSIX timer code is caused by the way the overrun accounting works. Depending on interval and expiry time values, the overrun can be larger than INT_MAX, but the accounting is int based. This basically makes the accounting values, which are visible to user space via timer_getoverrun(2) and siginfo::si_overrun, random. For example, a local user can cause a denial of service (signed integer overflow) via crafted mmap, futex, timer_create, and timer_settime system calls.

The alarm_timer_nsleep function in kernel/time/alarmtimer.c in the Linux kernel through 4.17.3 has an integer overflow via a large relative timeout because ktime_add_safe is not used.

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL.

Linux Kernel version 3.18 to 4.16 incorrectly handles an SG_IO ioctl on /dev/sg0 with dxfer_direction=SG_DXFER_FROM_DEV and an empty 6-byte cmdp. This may lead to copying up to 1000 kernel heap pages to the userspace. This has been fixed upstream in https://github.com/torvalds/linux/commit/a45b599ad808c3c982fdcdc12b0b8611c2f92824 already. The problem has limited scope, as users don't usually have permissions to access SCSI devices. On the other hand, e.g. the Nero user manual suggests doing `chmod o+r+w /dev/sg*` to make the devices accessible. NOTE: third parties dispute the relevance of this report, noting that the requirement for an attacker to have both the CAP_SYS_ADMIN and CAP_SYS_RAWIO capabilities makes it "virtually impossible to exploit.

An issue was discovered in the Linux kernel through 4.17.2. vbg_misc_device_ioctl() in drivers/virt/vboxguest/vboxguest_linux.c reads the same user data twice with copy_from_user. The header part of the user data is double-fetched, and a malicious user thread can tamper with the critical variables (hdr.size_in and hdr.size_out) in the header between the two fetches because of a race condition, leading to severe kernel errors, such as buffer over-accesses. This bug can cause a local denial of service and information leakage.

An issue was discovered in the Linux kernel through 4.17.2. Since the page allocator does not yield CPU resources to the owner of the oom_lock mutex, a local unprivileged user can trivially lock up the system forever by wasting CPU resources from the page allocator (e.g., via concurrent page fault events) when the global OOM killer is invoked. NOTE: the software maintainer has not accepted certain proposed patches, in part because of a viewpoint that "the underlying problem is non-trivial to handle.

A flaw was found affecting the Linux kernel before version 4.17. By mmap()ing a FUSE-backed file onto a process's memory containing command line arguments (or environment strings), an attacker can cause utilities from psutils or procps (such as ps, w) or any other program which makes a read() call to the /proc/<pid>/cmdline (or /proc/<pid>/environ) files to block indefinitely (denial of service) or for some controlled time (as a synchronization primitive for other attacks).

In net/socket.c in the Linux kernel through 4.17.1, there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat does not increment the file descriptor reference count, which allows close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash.

The "pingsender" executable used by the Firefox Health Report dynamically loads a system copy of libcurl, which an attacker could replace. This allows for privilege escalation as the replaced libcurl code will run with Firefox's privileges. Note: This attack requires an attacker have local system access and only affects OS X and Linux. Windows systems are not affected. This vulnerability affects Firefox < 57.

The compat_get_timex function in kernel/compat.c in the Linux kernel before 4.16.9 allows local users to obtain sensitive information from kernel memory via adjtimex.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 could allow a local user to overflow a buffer which may result in a privilege escalation to the DB2 instance owner. IBM X-Force ID: 143022.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 could allow a local user to overflow a buffer which may result in a privilege escalation to the DB2 instance owner. IBM X-Force ID: 142648.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 10.5 and 11.1, under specific or unusual conditions, could allow a local user to overflow a buffer which may result in a privilege escalation to the DB2 instance owner. IBM X-Force ID: 141624.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 10.5 and 11.1 is vulnerable to a buffer overflow, which could allow an authenticated local attacker to execute arbitrary code on the system as root. IBM X-Force ID: 140973.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 is vulnerable to stack based buffer overflow, caused by improper bounds checking which could lead an attacker to execute arbitrary code. IBM X-Force ID: 140210.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 contains a vulnerability that could allow a local user to overwrite arbitrary files owned by the DB2 instance owner. IBM X-Force ID: 140047.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 contains a vulnerability that could allow a local user to overwrite arbitrary files owned by the DB2 instance owner. IBM X-Force ID: 140046.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 contains a vulnerability that could allow a local user to overwrite arbitrary files owned by the DB2 instance owner. IBM X-Force ID: 140045.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 contains a vulnerability that could allow a local user to overwrite arbitrary files owned by the DB2 instance owner. IBM X-Force ID: 140044.

In the Linux kernel 4.13 through 4.16.11, ext4_read_inline_data() in fs/ext4/inline.c performs a memcpy with an untrusted length value in certain circumstances involving a crafted filesystem that stores the system.data extended attribute value in a dedicated inode.