CVE-2019-19338MediumCVSS 5.5

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.

Published
September 25, 2020
Last Modified
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🔗 CVE IDs covered (1)

CVE-2019-19338 →

📋 Description

Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability? One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.

🎯 Affected products1

  • cm1 kernel 5.4.91-3 on CBL Mariner 1.0

✅ Remediation

KBCBL-Mariner Releases (Security Update) — fixed build 5.4.91-3

🔗 References (2)