CVE-2021-47035 iommu/vt-d: Remove WO permissions on second-level paging entries
The Linux kernel allowed unsupported Write-Only permissions in IOMMU second-level paging, potentially bypassing intended read restrictions.
- 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-2021-47035?
CVE-2021-47035 is a high-severity vulnerability in Linux kernel, published on 28 Feb 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:
iommu/vt-d: Remove WO permissions on second-level paging entries
When the first level page table is used for IOVA translation, it only supports Read-Only and Read-Write permissions. The Write-Only permission is not supported as the PRESENT bit (implying Read permission) should always set. When using second level, we still give separate permissions that allows WriteOnly which seems inconsistent and awkward. We want to have consistent behavior. After moving to 1st level, we don't want things to work sometimes, and break if we use 2nd level for the same mappings. Hence remove this configuration.
Which versions are affected by CVE-2021-47035?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47035?
Apply the vendor's patch.
Is CVE-2021-47035 being exploited?
There is no known exploitation of CVE-2021-47035 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47035, GHSA-qp35-683c-hfxv, UBUNTU-CVE-2021-47035.