The vCPU context-switch implementation in Xen through 4.8.x improperly interacts with the Memory Protection Extensions (MPX) and Protection Key (PKU) features, which makes it easier for guest OS users to defeat ASLR and other protection mechanisms, aka XSA-220.

Multiple vulnerabilities have been discovered in the Xen hypervisor :

  - CVE-2017-10912     Jann Horn discovered that incorrectly handling of page     transfers might result in privilege escalation.

  - CVE-2017-10913 / CVE-2017-10914     Jann Horn discovered that race conditions in grant     handling might result in information leaks or privilege     escalation.

  - CVE-2017-10915     Andrew Cooper discovered that incorrect reference     counting with shadow paging might result in privilege     escalation.

  - CVE-2017-10916     Andrew Cooper discovered an information leak in the     handling of the Memory Protection Extensions (MPX) and     Protection Key (PKU) CPU features. This only affects     Debian stretch.

  - CVE-2017-10917     Ankur Arora discovered a NULL pointer dereference in     event polling, resulting in denial of service.

  - CVE-2017-10918     Julien Grall discovered that incorrect error handling in     physical-to-machine memory mappings may result in     privilege escalation, denial of service or an     information leak.

  - CVE-2017-10919     Julien Grall discovered that incorrect handling of     virtual interrupt injection on ARM systems may result in     denial of service.

  - CVE-2017-10920 / CVE-2017-10921 / CVE-2017-10922     Jan Beulich discovered multiple places where reference     counting on grant table operations was incorrect,     resulting in potential privilege escalation.

  - CVE-2017-12135     Jan Beulich found multiple problems in the handling of     transitive grants which could result in denial of     service and potentially privilege escalation.

  - CVE-2017-12136     Ian Jackson discovered that race conditions in the     allocator for grant mappings may result in denial of     service or privilege escalation. This only affects     Debian stretch.

  - CVE-2017-12137     Andrew Cooper discovered that incorrect validation of     grants may result in privilege escalation.

  - CVE-2017-12855     Jan Beulich discovered that incorrect grant status     handling, thus incorrectly informing the guest that the     grant is no longer in use.

  - XSA-235 (no CVE yet)

    Wei Liu discovered that incorrect locking of     add-to-physmap operations on ARM may result in denial of     service.

xen: various flaws (#1463247) blkif responses leak backend stack data [XSA-216] page transfer may allow PV guest to elevate privilege [XSA-217] Races in the grant table unmap code [XSA-218] x86:
insufficient reference counts during shadow emulation [XSA-219] x86:
PKRU and BND* leakage between vCPU-s [XSA-220] NULL pointer deref in event channel poll [XSA-221] (#1463231) stale P2M mappings due to insufficient error checking [XSA-222] ARM guest disabling interrupt may crash Xen [XSA-223] grant table operations mishandle reference counts [XSA-224] arm: vgic: Out-of-bound access when sending SGIs [XSA-225]

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for xen fixes several issues. These security issues were fixed :

  - CVE-2017-10911: blkif responses leaked backend stack     data, which allowed unprivileged guest to obtain     sensitive information from the host or other guests     (XSA-216, bsc#1042863)

  - CVE-2017-10912: Page transfer might have allowed PV     guest to elevate privilege (XSA-217, bsc#1042882)

  - CVE-2017-10913, CVE-2017-10914: Races in the grant table     unmap code allowed for informations leaks and     potentially privilege escalation (XSA-218, bsc#1042893)

  - CVE-2017-10915: Insufficient reference counts during     shadow emulation allowed a malicious pair of guest to     elevate their privileges to the privileges that XEN runs     under (XSA-219, bsc#1042915)

  - CVE-2017-10917: Missing NULL pointer check in event     channel poll allows guests to DoS the host (XSA-221,     bsc#1042924)

  - CVE-2017-10918: Stale P2M mappings due to insufficient     error checking allowed malicious guest to leak     information or elevate privileges (XSA-222, bsc#1042931)

  - CVE-2017-10922, CVE-2017-10921, CVE-2017-10920: Grant     table operations mishandled reference counts allowing     malicious guests to escape (XSA-224, bsc#1042938)

  - CVE-2017-10916: PKRU and BND* leakage between vCPU-s     might have leaked information to other guests (XSA-220,     bsc#1042923)

  - CVE-2017-9330: USB OHCI Emulation in qemu allowed local     guest OS users to cause a denial of service (infinite     loop) by leveraging an incorrect return value     (bsc#1042160)

  - CVE-2017-8309: Memory leak in the audio/audio.c allowed     remote attackers to cause a denial of service (memory     consumption) by repeatedly starting and stopping audio     capture (bsc#1037243)

  - CVE-2017-8112: hw/scsi/vmw_pvscsi.c allowed local guest     OS privileged users to cause a denial of service     (infinite loop and CPU consumption) via the message ring     page count (bsc#1036470)

  - CVE-2017-8905: Xen a failsafe callback, which might have     allowed PV guest OS users to execute arbitrary code on     the host OS (XSA-215, bsc#1034845).

  - CVE-2017-9503: The MegaRAID SAS 8708EM2 Host Bus Adapter     emulation support was vulnerable to a NULL pointer     dereference issue which allowed a privileged user inside     guest to crash the Qemu process on the host resulting in     DoS (bsc#1043297)

  - CVE-2017-9374: Missing free of 's->ipacket', causes a     host memory leak, allowing for DoS (bsc#1043074)

The update package also includes non-security fixes. See advisory for details.

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

xen: various flaws (#1463247) blkif responses leak backend stack data [XSA-216] page transfer may allow PV guest to elevate privilege [XSA-217] Races in the grant table unmap code [XSA-218] x86:
insufficient reference counts during shadow emulation [XSA-219] x86:
PKRU and BND* leakage between vCPU-s [XSA-220] stale P2M mappings due to insufficient error checking [XSA-222] ARM guest disabling interrupt may crash Xen [XSA-223] grant table operations mishandle reference counts [XSA-224] arm: vgic: Out-of-bound access when sending SGIs [XSA-225] NULL pointer deref in event channel poll [XSA-221] (#1463231)

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
103146	Debian DSA-3969-1 : xen - security update	Nessus	Debian Local Security Checks	critical
101638	Fedora 26 : xen (2017-5c6a9b07a3)	Nessus	Fedora Local Security Checks	critical
101350	SUSE SLES12 Security Update : xen (SUSE-SU-2017:1812-1)	Nessus	SuSE Local Security Checks	critical
101183	Fedora 24 : xen (2017-b3bdaf58bc)	Nessus	Fedora Local Security Checks	critical
101028	Fedora 25 : xen (2017-c3149b5fcb)	Nessus	Fedora Local Security Checks	critical

Detections

Analytics

CVE-2017-10916

high

Tenable Plugins

critical

critical

critical

critical

critical