CVE-2017-12855

NameCVE-2017-12855
DescriptionXen maintains the _GTF_{read,writ}ing bits as appropriate, to inform the guest that a grant is in use. A guest is expected not to modify the grant details while it is in use, whereas the guest is free to modify/reuse the grant entry when it is not in use. Under some circumstances, Xen will clear the status bits too early, incorrectly informing the guest that the grant is no longer in use. A guest may prematurely believe that a granted frame is safely private again, and reuse it in a way which contains sensitive information, while the domain on the far end of the grant is still using the grant. Xen 4.9, 4.8, 4.7, 4.6, and 4.5 are affected.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SuSE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-1132-1, DSA-3969-1
NVD severitylow (attack range: local)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
xen (PTS)wheezy4.1.4-3+deb7u9vulnerable
wheezy (security)4.1.6.lts1-9fixed
jessie4.4.1-9+deb8u9vulnerable
jessie (security)4.4.1-9+deb8u10fixed
buster, sid, stretch (security), stretch4.8.1-1+deb9u3fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
xensource(unstable)4.8.1-1+deb9u3low
xensourcejessie4.4.1-9+deb8u10lowDSA-3969-1
xensourcestretch4.8.1-1+deb9u3lowDSA-3969-1
xensourcewheezy4.1.6.lts1-9lowDLA-1132-1

Notes

https://xenbits.xen.org/xsa/advisory-230.html

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