An issue was discovered in Linux Foundation xapi in Citrix XenServer through 7.0. An authenticated read-only administrator can cancel tasks of other administrators.

ntp: disabling synchronization via crafted KoD packet

The ntpd client in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service via a number of crafted "KOD" messages.

xen: grant_table: Race conditions with maptrack free list handling (XSA-228)

Race condition in the grant table code in Xen 4.6.x through 4.9.x allows local guest OS administrators to cause a denial of service (free list corruption and host crash) or gain privileges on the host via vectors involving maptrack free list handling.

xen: x86 PV guests may be able to mask interrupts (XSA-202)

Xen through 4.8.x allows local x86 PV guest OS kernel administrators to cause a denial of service (host hang or crash) by modifying the instruction stream asynchronously while performing certain kernel operations.

xen: x86: missing NULL pointer check in VMFUNC emulation (XSA-203)

VMFUNC emulation in Xen 4.6.x through 4.8.x on x86 systems using AMD virtualization extensions (aka SVM) allows local HVM guest OS users to cause a denial of service (hypervisor crash) by leveraging a missing NULL pointer check.

Citrix XenMobile Server before 10.5.0.24 allows man-in-the-middle attackers to trigger HTTP 302 redirections via vectors involving the HTTP Host header and a cached page. NOTE: the vendor reports "our internal analysis of this issue concluded that this was not a valid vulnerability" because an exploitation scenario would involve a man-in-the-middle attack against a TLS session

xen: x86: PV privilege escalation via map_grant_ref (XSA-227)

arch/x86/mm.c in Xen allows local PV guest OS users to gain host OS privileges via vectors related to map_grant_ref.

xen: delimiter injection vulnerabilities in pygrub (XSA-198)

The pygrub boot loader emulator in Xen, when nul-delimited output format is requested, allows local pygrub-using guest OS administrators to read or delete arbitrary files on the host via NUL bytes in the bootloader configuration file.

xen: x86 task switch to VM86 mode mis-handled (XSA-192)

Xen 4.0.x through 4.7.x mishandle x86 task switches to VM86 mode, which allows local 32-bit x86 HVM guest OS users to gain privileges or cause a denial of service (guest OS crash) by leveraging a guest operating system that uses hardware task switching and allows a new task to start in VM86 mode.

xen: information leak in legacy x86 FPU/XMM initialization (XSA-165)

Xen 4.6.x, 4.5.x, 4.4.x, 4.3.x, and earlier do not initialize x86 FPU stack and XMM registers when XSAVE/XRSTOR are not used to manage guest extended register state, which allows local guest domains to obtain sensitive information from other domains via unspecified vectors.

Citrix XenApp 6.x before 6.5 HRP07 and 7.x before 7.9 and Citrix XenDesktop before 7.9 might allow attackers to weaken an unspecified security mitigation via vectors related to memory permission.

Citrix Worx Home for iOS before 10.3.6 and XenMobile MDX Toolkit for iOS before 10.3.6 might allow physically proximate attackers to bypass in-application Apple Touch ID authentication via unspecified vectors, related to an application requiring re-authentication.

Citrix XenServer 7.0 before Hotfix XS70E003, when a deployment has been upgraded from an earlier release, might allow remote attackers on the management network to "compromise" a host by leveraging credentials for an Active Directory account.

Citrix Studio before 7.6.1000, Citrix XenDesktop 7.x before 7.6 LTSR Cumulative Update 1 (CU1), and Citrix XenApp 7.5 and 7.6 allow attackers to set Access Policy rules on the XenDesktop Delivery Controller via unspecified vectors.

xen: x86: Privilege escalation in PV guests (XSA-182)

The PV pagetable code in arch/x86/mm.c in Xen 4.7.x and earlier allows local 32-bit PV guest OS administrators to gain host OS privileges by leveraging fast-paths for updating pagetable entries.

xen: unmediated PCI register access in qemu (xsa-131)

QEMU does not properly restrict write access to the PCI config space for certain PCI pass-through devices, which might allow local x86 HVM guests to gain privileges, cause a denial of service (host crash), obtain sensitive information, or possibly have other unspecified impact via unknown vectors.

Cross-site scripting (XSS) vulnerability in the Web User Interface in Citrix XenMobile Server 10.0, 10.1 before Rolling Patch 4, and 10.3 before Rolling Patch 1 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Citrix XenMobile MDX Toolkit before 9.0.4, when used to wrap iOS 8 applications, does not properly encrypt cached application data, which allows context-dependent attackers to obtain sensitive information by reading the cache.

Unspecified vulnerability in Citrix XenServer 6.2 Service Pack 1 and earlier allows attackers to cause a denial of service and obtain sensitive information by modifying the guest virtual hard disk (VHD).

qemu: incorrect banked access bounds checking in vga module

The VGA module in QEMU improperly performs bounds checking on banked access to video memory, which allows local guest OS administrators to execute arbitrary code on the host by changing access modes after setting the bank register, aka the "Dark Portal" issue.