Xen 4.6.x and earlier does not properly enforce limits on page order inputs for the (1) XENMEM_increase_reservation, (2) XENMEM_populate_physmap, (3) XENMEM_exchange, and possibly other HYPERVISOR_memory_op suboperations, which allows ARM guest OS administrators to cause a denial of service (CPU consumption, guest reboot, or watchdog timeout and host reboot) and possibly have unspecified other impact via unknown vectors.

The remote Redhat Enterprise Linux 5 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - xsa224 xen: grant table operations mishandle reference counts (XSA-224) (CVE-2017-10921)

  - The qemu implementation in libvirt before 1.3.0 and Xen allows local guest OS users to cause a denial of     service (host disk consumption) by writing to stdout or stderr. (CVE-2014-3672)

  - Heap-based buffer overflow in the PCNET controller in QEMU allows remote attackers to execute arbitrary     code by sending a packet with TXSTATUS_STARTPACKET set and then a crafted packet with TXSTATUS_DEVICEOWNS     set. (CVE-2015-3209)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

Multiple vulnerabilities have been discovered in the Xen hypervisor.
The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2015-8338     Julien Grall discovered that Xen on ARM was susceptible     to denial of service via long running memory operations.

  - CVE-2016-4480     Jan Beulich discovered that incorrect page table     handling could result in privilege escalation inside a     Xen guest instance.

  - CVE-2016-4962     Wei Liu discovered multiple cases of missing input     sanitising in libxl which could result in denial of     service.

  - CVE-2016-5242     Aaron Cornelius discovered that incorrect resource     handling on ARM systems could result in denial of     service.

  - CVE-2016-6258     Jeremie Boutoille discovered that incorrect pagetable     handling in PV instances could result in guest to host     privilege escalation.

eepro100: Prevent two endless loops [CVE-2015-8345], pcnet: fix rx buffer overflow [CVE-2015-7512], ui: vnc: avoid floating point exception [CVE-2015-8504], additional patch for [XSA-158, CVE-2015-8338] long running memory operations on ARM [XSA-158, CVE-2015-8338] XENMEM_exchange error handling issues [XSA-159, CVE-2015-8339, CVE-2015-8340] libxl leak of pv kernel and initrd on error [XSA-160, CVE-2015-8341] ---- heap buffer overflow vulnerability in pcnet emulator [XSA-162, CVE-2015-7504], virtual PMU is unsupported [XSA-163]

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

eepro100: Prevent two endless loops [CVE-2015-8345] (#1285215), pcnet:
fix rx buffer overflow [CVE-2015-7512], ui: vnc: avoid floating point exception [CVE-2015-8504], additional patch for [XSA-158, CVE-2015-8338] long running memory operations on ARM [XSA-158, CVE-2015-8338] XENMEM_exchange error handling issues [XSA-159, CVE-2015-8339, CVE-2015-8340] libxl leak of pv kernel and initrd on error [XSA-160, CVE-2015-8341] ---- heap buffer overflow vulnerability in pcnet emulator [XSA-162, CVE-2015-7504], virtual PMU is unsupported [XSA-163]

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

ID	Name	Product	Family	Severity
199537	RHEL 5 : xen (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	critical
92614	Debian DSA-3633-1 : xen - security update (Bunker Buster)	Nessus	Debian Local Security Checks	high
89151	Fedora 23 : xen-4.5.2-5.fc23 (2015-12a089920e)	Nessus	Fedora Local Security Checks	critical
89135	Fedora 22 : xen-4.5.2-5.fc22 (2015-08e4af5a20)	Nessus	Fedora Local Security Checks	critical

Detections

Analytics

CVE-2015-8338

medium

Tenable Plugins

critical

high

critical

critical