CVE-2023-53501 iommu/amd/iommu_v2: Fix pasid_state refcount dec hit 0 warning on pasid unbind

What is CVE-2023-53501?

CVE-2023-53501 is a medium-severity vulnerability in Linux kernel, published on 1 Oct 2025. 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/amd/iommu_v2: Fix pasid_state refcount dec hit 0 warning on pasid unbind

When unbinding pasid - a race condition exists vs outstanding page faults.

To prevent this, the pasid_state object contains a refcount. * set to 1 on pasid bind * incremented on each ppr notification start * decremented on each ppr notification done * decremented on pasid unbind

Since refcount_dec assumes that refcount will never reach 0: the current implementation causes the following to be invoked on pasid unbind: REFCOUNT_WARN("decrement hit 0; leaking memory")

Fix this issue by changing refcount_dec to refcount_dec_and_test to explicitly handle refcount=1.

Which versions are affected by CVE-2023-53501?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2023-53501?

Apply the vendor's patch.

Is CVE-2023-53501 being exploited?

There is no known exploitation of CVE-2023-53501 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

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

Also known as BELL-CVE-2023-53501, DEBIAN-CVE-2023-53501, GHSA-76q6-633x-65vj, UBUNTU-CVE-2023-53501.