CVE-2026-53281
HighCVSS 8.8Exploitation Probability (EPSS)
Low risk2th percentile — higher than 2% of all known CVEs
Summary
In the Linux kernel IOMMU subsystem for Intel VT-d, a vulnerability was found causing NULL pointer dereference or refcount corruption. The issue occurs when teardown operations are executed without checking if the dev_pasid structure exists, potentially leading to system crashes or memory safety violations.
Risk Assessment
The organization faces risk of system crashes (kernel panic) or potential exploitation for privilege escalation via use-after-free. The vulnerability is particularly dangerous in virtualized environments relying on Intel VT-d.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit addressing the issue). Monitor security advisories from your Linux distribution and apply the patch once officially released.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Avoid NULL pointer dereference or refcount corruption Commit 60f030f7418d ("iommu/vt-d: Avoid use of NULL after WARN_ON_ONCE") fixed a NULL pointer dereference in an unlikely situation partly. If dev_pasid is not found in the dev_pasids list, it remains NULL. However, the teardown operations are executed unconditionally, this lead to a NULL pointer dereference or refcount corruption. If the domain was never attached to this IOMMU, info will be NULL, which would cause an immediate dereference when checking --info->refcnt. Even if info is not NULL, decrementing the refcount without having removed a valid PASID might unbalance the count. This could lead to premature dropping of the refcount to 0, potentially causing a use-after-free for the remaining active devices sharing the domain. Fix it by returning early if dev_pasid is NULL, before executing the teardown operations. Issue found by AI review and suggested by Kevin Tian. https://sashiko.dev/#/patchset/20260421031347.1408890-1-zhenzhong.duan%40intel.com