CVE-2026-43253: Linux kernel · iommu/amd: move wait_on_sem() out of spinlock
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.5 High · fixed in f2f65b28d802a667119147444ec2ae33eebf9a58 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in f2f65b28d802a667119147444ec2ae33eebf9a58, e15768e68820142077bbca402d8e902f64ade1b0, d2a0cac10597068567d336e85fa3cbdbe8ca62bf +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
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.
References
- git.kernel.org/stable/c/f2f65b28d802a667119147444ec2ae33eebf9a58 (opens in a new tab)
- git.kernel.org/stable/c/715c263119fd1b918a9fcbd8a36ea5b604a46324 (opens in a new tab)
- git.kernel.org/stable/c/e15768e68820142077bbca402d8e902f64ade1b0 (opens in a new tab)
- git.kernel.org/stable/c/496269d12072ecb219826485bdbec70c92a8eef5 (opens in a new tab)
- git.kernel.org/stable/c/d2a0cac10597068567d336e85fa3cbdbe8ca62bf (opens in a new tab)