Bug 1891089 (CVE-2020-27674) - CVE-2020-27674 xen: x86 PV guest INVLPG-like flushes may leave stale TLB entries (XSA-286)
Summary: CVE-2020-27674 xen: x86 PV guest INVLPG-like flushes may leave stale TLB entr...
Alias: CVE-2020-27674
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1891092
Blocks: 1891100
TreeView+ depends on / blocked
Reported: 2020-10-23 18:48 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-02-16 19:01 UTC (History)
25 users (show)

Fixed In Version:
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Doc Text:
A flaw was found in the Xen hypercalls with INVLPG-like behavior used by x86 PV guests to invalidate TLB entries. This flaw allows a malicious unprivileged guest user to escalate their privileges to the kernel level within the guest.
Clone Of:
Last Closed: 2020-11-02 20:21:20 UTC

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Description Guilherme de Almeida Suckevicz 2020-10-23 18:48:13 UTC
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.

Comment 1 Guilherme de Almeida Suckevicz 2020-10-23 18:54:44 UTC
Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1891092]

Comment 2 Mauro Matteo Cascella 2020-11-02 14:37:59 UTC

Name: the Xen project

Comment 3 Mauro Matteo Cascella 2020-11-02 14:40:06 UTC
External References:


Comment 5 Product Security DevOps Team 2020-11-02 20:21:20 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 7 Mauro Matteo Cascella 2020-11-03 11:23:59 UTC

There is no known mitigation for this flaw apart from applying the patch.

Comment 8 RaTasha Tillery-Smith 2020-11-11 17:46:50 UTC

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/.

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