An issue was discovered in the Linux kernel 3.11 through 5.10.16, as used by Xen. To service requests to the PV backend, the driver maps grant references provided by the frontend. In this process, errors may be encountered. In one case, an error encountered earlier might be discarded by later processing, resulting in the caller assuming successful mapping, and hence subsequent operations trying to access space that wasn't mapped. In another case, internal state would be insufficiently updated, preventing safe recovery from the error. This affects drivers/block/xen-blkback/blkback.c.

Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef ("ovl: stack file ops"). This was fixed in kernel version 5.8 by commits 56230d9 ("ovl: verify permissions in ovl_path_open()"), 48bd024 ("ovl: switch to mounter creds in readdir") and 05acefb ("ovl: check permission to open real file"). Additionally, commits 130fdbc ("ovl: pass correct flags for opening real directory") and 292f902 ("ovl: call secutiry hook in ovl_real_ioctl()") in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da ("ovl: do not fail because of O_NOATIMEi") in kernel 5.11.

In a Linux KVM guest that has PV TLB enabled, a process in the guest kernel may be able to read memory locations from another process in the same guest. This problem is limit to the host running linux kernel 4.10 with a guest running linux kernel 4.16 or later. The problem mainly affects AMD processors but Intel CPUs cannot be ruled out.

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.

A flaw was found in the Linux kernel in the function hid_debug_events_read() in drivers/hid/hid-debug.c file which may enter an infinite loop with certain parameters passed from a userspace. A local privileged user ("root") can cause a system lock up and a denial of service. Versions from v4.18 and newer are vulnerable.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 binaries load shared libraries from an untrusted path potentially giving low privilege user full access to the DB2 instance account by loading a malicious shared library. IBM X-Force ID: 149640.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 could allow a local unprivileged user to overwrite files on the system which could cause damage to the database. IBM X-Force ID: 149429.

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 obtain root access by exploiting a symbolic link attack to read/write/corrupt a file that they originally did not have permission to access. IBM X-Force ID: 148804.

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 execute arbitrary code due to a format string error. IBM X-Force ID: 143023.

IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5 and 11.1 binaries load shared libraries from an untrusted path potentially giving low privilege users full access to the DB2 instance account by loading a malicious shared library. IBM X-Force ID: 140972.

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 execute arbitrary code and conduct DLL hijacking attacks. IBM X-Force ID: 140209.

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.

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.