UBUNTU-CVE-2016-9386

The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest users to gain privileges via vectors involving "unexpected" base/limit values...

DEBIAN-CVE-2016-1922

QEMU aka Quick Emulator built with the TPR optimization for 32-bit Windows guests support is vulnerable to a null pointer dereference flaw. It occurs while doing I/O port write operations via hmp interface. In that, 'currentcpu' remains null, which leads to the null pointer dereference. A user or...

PT-2016-3002 · Qemu +3 · Qemu +3

Name of the Vulnerable Software and Affected Versions: QEMU affected versions not specified Description: The issue is related to a memory leak in the v9fs device unrealize common function, which can be exploited by local privileged guest OS users to cause a denial of service. This can lead to hos...

Fedora 25 : xen (2016-92e3ea2d1b)

two security flaws 1406840 x86 PV guests may be able to mask interrupts XSA-202, CVE-2016-10024 x86: missing NULL pointer check in VMFUNC emulation XSA-203, CVE-2016-10025 x86: Mishandling of SYSCALL singlestep during emulation XSA-204, CVE-2016-10013 1406260 Note that Tenable Network Security ha...

PT-2016-7786 · Linux +5 · Linux Kernel +5

Name of the Vulnerable Software and Affected Versions: Linux kernel versions prior to 4.10 Description: The issue mismanages the BP and OF exceptions in the Linux kernel, allowing guest OS users to cause a denial of service by declining to handle an exception thrown by an L2 guest. Recommendation...

SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2016:3208-1)

This update for xen fixes the following issues : - A Mishandling of SYSCALL singlestep during emulation which could have lead to privilege escalation. XSA-204, bsc1016340, CVE-2016-10013 - CMPXCHG8B emulation failed to ignore operand size override which could have lead to information disclosure...

x86: missing NULL pointer check in VMFUNC emulation

ISSUE DESCRIPTION When support for the Intel VMX VMFUNC leaf 0 was added, a new optional function pointer hvmemulvmfunc was added to the hvmemulateops table. As is intended, that new function pointer is NULL on non-VMX hardware, including AMD SVM hardware. However at a call site, the necessary NU...

x86 PV guests may be able to mask interrupts

ISSUE DESCRIPTION Certain PV guest kernel operations page table writes in particular need emulation, and use Xen's general x86 instruction emulator. This allows a malicious guest kernel which asynchronously modifies its instruction stream to effect the clearing of EFLAGS.IF from the state used to...

Fedora 23 : xen (2016-cc2916dcf4)

ARM guests may induce host asynchronous abort XSA-201, CVE-2016-9815, CVE-2016-9816, CVE-2016-9817, CVE-2016-9818 1399747 qemu: Divide by zero vulnerability in cirrusdocopy 1399055 CVE-2016-9921, CVE-2016-9922 Qemu: 9pfs: memory leakage via proxy/handle callbacks 1402278 qemu ioport array overflo...

Fedora 25 : xen (2016-1b868c23a9)

x86 CMPXCHG8B emulation fails to ignore operand size override XSA-200, CVE-2016-9932 1404262 ---- ARM guests may induce host asynchronous abort XSA-201, CVE-2016-9815, Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website...

x86: Mishandling of SYSCALL singlestep during emulation

ISSUE DESCRIPTION The typical behaviour of singlestepping exceptions is determined at the start of the instruction, with a DB trap being raised at the end of the instruction. SYSCALL and SYSRET, although we don't implement it behave differently because the typical behaviour allows userspace to...

ALPINE-CVE-2016-9101

Memory leak in hw/net/eepro100.c in QEMU aka Quick Emulator allows local guest OS administrators to cause a denial of service memory consumption and QEMU process crash by repeatedly unplugging an i8255x PRO100 NIC device...

Debian DSA-3729-1 : xen - security update

Multiple vulnerabilities have been discovered in the Xen hypervisor. The Common Vulnerabilities and Exposures project identifies the following problems : - CVE-2016-7777 XSA-190 Jan Beulich from SUSE discovered that Xen does not properly honor CR0.TS and CR0.EM for x86 HVM guests, potentially...

qemu ioport array overflow

ISSUE DESCRIPTION The code in qemu which implements ioport read/write looks up the specified ioport address in a dispatch table. The argument to the dispatch function is a uint32t, and is used without a range check, even though the table has entries for only 2^16 ioports. When qemu is used as a...

FreeBSD : xen-kernel -- x86: Disallow L3 recursive pagetable for 32-bit PV guests (45ca25b5-ba4d-11e6-ae1b-002590263bf5)

The Xen Project reports : On real hardware, a 32-bit PAE guest must leave the USER and RW bit clear in L3 pagetable entries, but the pagetable walk behaves as if they were set. The L3 entries are cached in processor registers, and don't actually form part of the pagewalk. When running a 32-bit PV...

FreeBSD : xen-kernel -- CR0.TS and CR0.EM not always honored for x86 HVM guests (4d7cf654-ba4d-11e6-ae1b-002590263bf5)

The Xen Project reports : Instructions touching FPU, MMX, or XMM registers are required to raise a Device Not Available Exception NM when either CR0.EM or CR0.TS are set. Their AVX or AVX-512 extensions would consider only CR0.TS. While during normal operation this is ensured by the hardware, if ...

x86 segment base write emulation lacking canonical address checks

ISSUE DESCRIPTION Both writes to the FS and GS register base MSRs as well as the WRFSBASE and WRGSBASE instructions require their input values to be canonical, or a GP fault will be raised. When the use of those instructions by the hypervisor was enabled, the previous guard against GP faults havi...

x86 task switch to VM86 mode mis-handled

ISSUE DESCRIPTION LDTR, just like TR, is purely a protected mode facility. Hence even when switching to a VM86 mode task, LDTR loading needs to follow protected mode semantics. This was violated by the code. IMPACT On SVM AMD hardware: a malicious unprivileged guest process can escalate its...

x86 null segments not always treated as unusable

ISSUE DESCRIPTION The Xen x86 emulator erroneously failed to consider the unusability of segments when performing memory accesses. The intended behaviour is as follows: The user data segment %ds, %es, %fs and %gs selectors may be NULL in 32-bit to prevent access. In 64-bit, NULL has a special...

Fedora 25 : xen (2016-1d8429b89f)

fix build problem with glibc 2.24 x86: Disallow L3 recursive pagetable for 32-bit PV guests XSA-185, CVE-2016-7092 x86: Mishandling of instruction pointer truncation during emulation XSA-186, CVE-2016-7093 x86 HVM: Overflow of shctxt-segreg XSA-187, CVE-2016-7094 pandoc documentation has dependen...