CVE-2026-90240 iommu/vt-d: Flush context cache with correct SID when tearing down aliases

What is CVE-2026-90240?

CVE-2026-90240 is a high-severity use after free vulnerability in Linux, published on 17 Sep 2026. 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: Flush context cache with correct SID when tearing down aliases

domain_context_clear_one() and device_pasid_table_teardown() are both invoked once per DMA alias of a device. Each function locates the context entry using the bus/devfn pair provided by the pci_for_each_dma_alias() callback, then calls intel_context_flush_no_pasid(), which constructs a device-selective context-cache invalidation from info->bus and info->devfn (that is, always the requester ID of the device itself).

As a result, for every alias other than the device’s own RID, the context entry that was just cleared in memory is never invalidated in the context cache. Hardware may continue using that stale cached entry. In the scalable-mode teardown path, intel_pasid_free_table() can then free the PASID directory still referenced by that stale entry, allowing the IOMMU to walk freed memory.

Fix this by passing the source ID of the entry being torn down to intel_context_flush_no_pasid(), instead of deriving it from @info.

Which versions are affected by CVE-2026-90240?

How do I fix CVE-2026-90240?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-90240 being exploited?

There is no known exploitation of CVE-2026-90240 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-90240, DEBIAN-CVE-2026-90240, GHSA-rghx-9889-ffmw, UBUNTU-CVE-2026-90240.