An issue was discovered in all versions of Xen allowing x86 PV guest OS users to gain guest OS privileges by modifying kernel memory contents, because invalidation of TLB entries is mishandled during use of an INVLPG-like attack technique.
Created xen tracking bugs for this issue: Affects: fedora-all [bug 1891092]
Acknowledgments: Name: the Xen project
External References: https://xenbits.xen.org/xsa/advisory-286.html
Upstream fix: https://xenbits.xen.org/xsa/xsa286-unstable/0001-x86-pv-Drop-FLUSH_TLB_GLOBAL-in-do_mmu_update-for-XP.patch https://xenbits.xen.org/xsa/xsa286-unstable/0002-x86-pv-Flush-TLB-in-response-to-paging-structure-cha.patch
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2020-27674
Mitigation: There is no known mitigation for this flaw apart from applying the patch.
Statement: This flaw has been rated as having a security impact of Low, and is not currently planned to be addressed in future updates of Red Hat Enterprise Linux 5. Red Hat Enterprise Linux 5 is now in the Extended Life Phase of the support and maintenance life cycle. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.