Xen 4.0.x and 4.1.x incorrectly releases a grant reference when releasing a
non-v1, non-transitive grant, which allows local guest administrators to
cause a denial of service (host crash), obtain sensitive information, or
possible have other impacts via unspecified vectors.
This one never made it into a bug, but has been fixed with other stabilizations. Will be resolved with next Xen GLSA release.
This issue was resolved and addressed in
GLSA 201309-24 at http://security.gentoo.org/glsa/glsa-201309-24.xml
by GLSA coordinator Chris Reffett (creffett).