Xen through 4.8.x does not validate a vCPU array index upon the sending of an SGI, which allows guest OS users to cause a denial of service (hypervisor crash), aka XSA-225.

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.

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
101638	Fedora 26 : xen (2017-5c6a9b07a3)	Nessus	Fedora 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-2017-10923

medium

Tenable Plugins

critical

critical

critical