CVE-2019-19338

Name: CVE-2019-19338
Creator: NVD / NIST
Published: 2020-07-13T17:15:11.247+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.46%

Last modified Jun 17, 2026

CVE-2019-19338 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A flaw was found in the fix for CVE-2019-11135, in the Linux upstream kernel versions before 5.5 where, the way Intel CPUs handle speculative execution of instructions when a TSX Asynchronous Abort (TAA) error occurs. When a guest is running on a host CPU affected by the TAA flaw (TAA_NO=0), but is not affected by the MDS issue (MDS_NO=1), the guest was to clear the affected buffers by using a VERW instruction mechanism. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

Description

A flaw was found in the fix for CVE-2019-11135, in the Linux upstream kernel versions before 5.5 where, the way Intel CPUs handle speculative execution of instructions when a TSX Asynchronous Abort (TAA) error occurs. When a guest is running on a host CPU affected by the TAA flaw (TAA_NO=0), but is not affected by the MDS issue (MDS_NO=1), the guest was to clear the affected buffers by using a VERW instruction mechanism. But when the MDS_NO=1 bit was exported to the guests, the guests did not use the VERW mechanism to clear the affected buffers. This issue affects guests running on Cascade Lake CPUs and requires that host has 'TSX' enabled. Confidentiality of data is the highest threat associated with this vulnerability.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.46%

36.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 5.5
Redhat	Enterprise Linux	6.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-19338Issue Tracking, Patch, Third Party Advisory
https://software.intel.com/security-software-guidance/insights/deep-dive-intel-transactional-synchronization-extensions-intel-tsx-asynchronous-abortThird Party Advisory
https://www.openwall.com/lists/oss-security/2019/12/10/3Mailing List, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-19338Issue Tracking, Patch, Third Party Advisory
https://software.intel.com/security-software-guidance/insights/deep-dive-intel-transactional-synchronization-extensions-intel-tsx-asynchronous-abortThird Party Advisory
https://www.openwall.com/lists/oss-security/2019/12/10/3Mailing List, Patch, Third Party Advisory

Timeline

Published: Jul 13, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-19338?

How severe is CVE-2019-19338?

CVE-2019-19338 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.

How do I fix CVE-2019-19338?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-19338?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST