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CVE Record

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

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel issue in the AMD IOMMU v2 PASID handling path. A race during PASID unbind can mishandle an internal reference count and trigger a kernel warning about leaking memory. The provided sources do not show active exploitation, business impact, or a remote attack path.

Executive priority

Treat as a targeted kernel maintenance item, not an emergency based on current evidence. Prioritize normal patch cycles for Linux systems, with higher attention where AMD IOMMU v2 or PASID features are relevant.

Technical view

The bug is in iommu/amd/iommu_v2. PASID state is reference-counted across bind, page request notifications, completion, and unbind. On unbind, refcount_dec could hit zero unexpectedly; the fix changes this to refcount_dec_and_test so refcount=1 is handled explicitly.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions that exercise the AMD IOMMU v2 PASID path. The source bundle does not identify affected distributions, default configurations, cloud platforms, or remotely reachable services.

Exploitation context

CISA KEV status is false, and the provided sources do not report exploitation in the wild. The bundle describes a race condition and kernel refcount warning, but does not provide exploitability, attacker prerequisites, or impact beyond the resolved kernel bug.

Researcher notes

Evidence is sparse. The CVE record describes the fix mechanics but lacks CVSS, CWE, impact statement, privilege requirements, and exploit status. Avoid broad claims beyond affected Linux kernel code paths and referenced upstream stable fixes.

Mitigation direction

  • Inventory Linux kernel versions against vendor advisories for CVE-2023-53501.
  • Apply Linux distribution kernel updates that include the upstream stable fixes.
  • Prioritize systems using AMD IOMMU v2 or PASID-related functionality.
  • If unsupported, plan upgrade to a maintained kernel branch.
  • Monitor vendor guidance for distribution-specific fixed package versions.

Validation and detection

  • Confirm running kernel versions on Linux assets.
  • Check whether vendor kernel advisories reference CVE-2023-53501 or the stable commits.
  • Review kernel logs for related AMD IOMMU PASID refcount warnings.
  • Verify patched kernels are active after reboot.
  • Document any systems deferred from patching and compensating controls.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2023-53501 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux8bc54824da4e8fcf0ed679cf09ac32f23d83254a, 8bc54824da4e8fcf0ed679cf09ac32f23d83254a, 8bc54824da4e8fcf0ed679cf09ac32f23d83254a, 8bc54824da4e8fcf0ed679cf09ac32f23d83254a, 8bc54824da4e8fcf0ed679cf09ac32f23d83254aunaffected
LinuxLinux5.15, 0, 5.15.132, 6.1.53, 6.4.16, 6.5.3, 6.6affected
Weakness

CWE details

No CWE listed

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