CVE-2024-46794 x86/tdx: Fix data leak in mmio_read()

Low 3.3 Published Updated

A flaw in the Linux kernel's TDX module leaks stack data to the VMM during MMIO reads, allowing potential information disclosure.

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-2024-46794?

CVE-2024-46794 is a low-severity vulnerability in Linux kernel, published on 18 Sep 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

x86/tdx: Fix data leak in mmio_read()

The mmio_read() function makes a TDVMCALL to retrieve MMIO data for an address from the VMM.

Sean noticed that mmio_read() unintentionally exposes the value of an initialized variable (val) on the stack to the VMM.

This variable is only needed as an output value. It did not need to be passed to the VMM in the first place.

Do not send the original value of *val to the VMM.

[ dhansen: clarify what 'val' is used for. ]

Which versions are affected by CVE-2024-46794?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-46794?

Apply the vendor's patch.

Is CVE-2024-46794 being exploited?

There is no known exploitation of CVE-2024-46794 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-53295, BELL-CVE-2024-46794, DEBIAN-CVE-2024-46794, GHSA-cx75-fvjc-vvr8, UBUNTU-CVE-2024-46794.

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