Multiple vulnerabilities have been discovered in the Xen hypervisor. The Common Vulnerabilities and Exposures project identifies the following problems:
(XSA 45) several long latency operations are not preemptible.
Some page table manipulation operations for PV guests were not made preemptible, allowing a malicious or buggy PV guest kernel to mount a denial of service attack affecting the whole system.
(XSA 49) VT-d interrupt remapping source validation flaw for bridges.
Due to missing source validation on interrupt remapping table entries for MSI interrupts set up by bridge devices, a malicious domain with access to such a device can mount a denial of service attack affecting the whole system.
(XSA 50) grant table hypercall acquire/release imbalance.
When releasing a particular, non-transitive grant after doing a grant copy operation, Xen incorrectly releases an unrelated grant reference, leading possibly to a crash of the host system. Furthermore information leakage or privilege escalation cannot be ruled out.
For the oldstable distribution (squeeze), these problems have been fixed in version 4.0.1-5.11.
For the stable distribution (wheezy), these problems have been fixed in version 4.1.4-3+deb7u1.
For the testing distribution (jessie), these problems have been fixed in version 4.1.4-4.
For the unstable distribution (sid), these problems have been fixed in version 4.1.4-4.
We recommend that you upgrade your xen packages.