CVE-2018-12893

NameCVE-2018-12893
DescriptionAn issue was discovered in Xen through 4.10.x. One of the fixes in XSA-260 added some safety checks to help prevent Xen livelocking with debug exceptions. Unfortunately, due to an oversight, at least one of these safety checks can be triggered by a guest. A malicious PV guest can crash Xen, leading to a Denial of Service. All Xen systems which have applied the XSA-260 fix are vulnerable. Only x86 systems are vulnerable. ARM systems are not vulnerable. Only x86 PV guests can exploit the vulnerability. x86 HVM and PVH guests cannot exploit the vulnerability. An attacker needs to be able to control hardware debugging facilities to exploit the vulnerability, but such permissions are typically available to unprivileged users.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-1577-1, DSA-4236-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
xen (PTS)jessie, jessie (lts)4.4.4lts5-0+deb8u1fixed
stretch (security), stretch (lts), stretch4.8.5.final+shim4.10.4-1+deb9u12fixed
buster (security), buster, buster (lts)4.11.4+107-gef32c7afa2-1fixed
bullseye4.14.6-1fixed
bullseye (security)4.14.5+94-ge49571868d-1fixed
bookworm4.17.3+10-g091466ba55-1~deb12u1fixed
sid, trixie4.17.3+36-g54dacb5c02-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
xensourcejessie4.4.4lts4-0+deb8u1DLA-1577-1
xensourcestretch4.8.3+xsa267+shim4.10.1+xsa267-1+deb9u9DSA-4236-1
xensource(unstable)4.8.3+xsa267+shim4.10.1+xsa267-1+deb9u9

Notes

https://xenbits.xen.org/xsa/advisory-265.html

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