CVE-2026-90426 iommu/tegra241-cmdqv: Free the error IRQ before tearing down VINTFs
A use-after-free vulnerability in the Linux kernel Tegra241 IOMMU driver allows local attackers to cause a system crash or potentially execute code during device teardown.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90426?
CVE-2026-90426 is an 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/tegra241-cmdqv: Free the error IRQ before tearing down VINTFs
tegra241_cmdqv_remove() tears each VINTF down first, then calls free_irq(). Tearing a VINTF down frees vintf0 and clears cmdqv->vintfs[0]. An error in that window makes tegra241_cmdqv_isr() read the stale slot and hand it to tegra241_vintf0_handle_error(), which dereferences a NULL or freed pointer.
Free the IRQ before tearing the VINTFs down. free_irq() waits for in-flight handlers to finish and blocks new ones, so no ISR can observe a VINTF as it is torn down.
Note: a user-owned VINTF (viommu) could outlive this teardown, which unmaps cmdqv->base and frees cmdqv->vintfs, so a later viommu close then touches freed memory. This is neither introduced nor fixed here: a physical IOMMU is not a pluggable device, so iommufd by design holds no reference on the one behind a viommu, and this teardown is not expected while that viommu is still alive.
Which versions are affected by CVE-2026-90426?
How do I fix CVE-2026-90426?
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-2026-90426 being exploited?
There is no known exploitation of CVE-2026-90426 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90426, DEBIAN-CVE-2026-90426, GHSA-r9gp-2p3g-7gww, UBUNTU-CVE-2026-90426.