Vulnerability in Linux Kernel
CVE-2019-19338
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.
EPSS: 0.005 (37.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Linux Linux_kernel
- [Unknown] Linux Kernel — versions before 5.5
- Redhat Enterprise_linux — versions 6.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- secalert@redhat.com (Patch, Mailing List, Third Party Advisory, x_refsource_MISC)
- secalert@redhat.com (x_refsource_CONFIRM, Patch, Third Party Advisory, Issue Tracking)
- secalert@redhat.com (Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2019-19338?
- CVE-2019-19338 is a medium-severity vulnerability in Linux Kernel, classified under Observable Discrepancy. CVSS score: 5.5/10. Published 2020-07-13.
- How severe is CVE-2019-19338?
- Medium severity. CVSS v3 base score is 5.5 out of 10.
- Is CVE-2019-19338 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.