CVE-2026-43253

iommu/amd: move wait_on_sem() out of spinlock

HIGH
7.5
CVSS Score
Published: May 6, 2026 at 11:28 AM UTC
Updated: October 19, 2026 at 08:18 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: iommu/amd: move wait_on_sem() out of spinlock With iommu.strict=1, the existing completion wait path can cause soft lockups under stressed environment, as wait_on_sem() busy-waits under the spinlock with interrupts disabled. Move the completion wait in iommu_completion_wait() out of the spinlock. wait_on_sem() only polls the hardware-updated cmd_sem and does not require iommu->lock, so holding the lock during the busy wait unnecessarily increases contention and extends the time with interrupts disabled.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.9 ≤ v < 6.6.1286.13 ≤ v < 6.18.166.19 ≤ v < 6.19.66.7 ≤ v < 6.12.754.94bf5beef578e46393f11eb69dda7d17a065e05ff
Vendor states this is fixed in 496269d12072ecb219826485bdbec70c92a8eef5 (fixed)
Vendor states this is fixed in 715c263119fd1b918a9fcbd8a36ea5b604a46324 (fixed)
Vendor states this is fixed in d2a0cac10597068567d336e85fa3cbdbe8ca62bf (fixed)
Vendor states this is fixed in e15768e68820142077bbca402d8e902f64ade1b0 (fixed)
Vendor states this is fixed in f2f65b28d802a667119147444ec2ae33eebf9a58 (fixed)
Vendor states this is fixed in 4.9 (unaffected)
Vendor states this is fixed in 6.12.75 (unaffected)
Vendor states this is fixed in 6.18.16 (unaffected)
Vendor states this is fixed in 6.19.6 (unaffected)
Vendor states this is fixed in 6.6.128 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHLinux
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-667CWE-833

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