In the Linux kernel, the following vulnerability has been resolved:
xen-netback: Zero out sring pointers on unmap
If xenvif map frontend data rings() fails when a ring is already mapped,
it unmaps them via xenvif unmap frontend data rings() which keeps the
ring pointers unchanged. xenvif connect data()'s cleanup path calls
xenvif disconnect queue() which in turn calls
xenvif unmap frontend data rings() again, which will attempt to unmap the
pointers a second time.
Zero out the ring pointers after they are unmapped to avoid this issue.
This is XSA-532