CVE-2023-53501: Linux Kernel

Medium severity, CVSS 4.7. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 5.15, before 5.15.132 (fixed in 5.15.132); from 5.16, before 6.1.53 (fixed in 6.1.53); from 6.2, before 6.4.16 (fixed in 6.4.16); from 6.5, before 6.5.3 (fixed in 6.5.3)

Published 2025-10-01. Last modified 2026-06-17.