CVE-2019-19338 Information disclosure in Linux Kernel
Guests on affected Intel Cascade Lake CPUs with TSX enabled may leak sensitive data due to improper buffer clearing during speculative execution errors.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-19338?
CVE-2019-19338 is a medium-severity vulnerability in Linux kernel, published on 13 Jul 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2019-19338?
It affects 2 products.
Products include Linux kernel, Redhat Enterprise Linux.
How do I fix CVE-2019-19338?
Apply the vendor's patch.
Is CVE-2019-19338 being exploited?
There is no known exploitation of CVE-2019-19338 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as GHSA-qv7j-3q84-2q98, UBUNTU-CVE-2019-19338.