NVD / CVE Program· CNA Linux

CVE-2026-43253: iommu/amd: move wait_on_sem() out of spinlock

Noroxi assessment

Priority: Monitor (action score 30/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.37% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: Linux Linux 496269d12072ecb219826485bdbec70c92a8eef5, 69d9339c02eddfc2a345be7220651068a3684383, 715c263119fd1b918a9fcbd8a36ea5b604a46324.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 496269d12072ecb219826485bdbec70c92a8eef5, 69d9339c02eddfc2a345be7220651068a3684383, 715c263119fd1b918a9fcbd8a36ea5b604a46324 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available

Published: May 6, 2026
Updated: Oct 30, 2026
EPSS: 0.3% · 30th percentile
CWE: CWE-667

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.5; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel4.9 and later · before 6.6.128
linux linux kernel6.7 and later · before 6.12.75
linux linux kernel6.13 and later · before 6.18.16
linux linux kernel6.19 and later · before 6.19.6

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 4.9affected
- 4bf5beef578e46393f11eb69dda7d17a065e05ff and later · before 69d9339c02eddfc2a345be7220651068a3684383affected · git
- 4bf5beef578e46393f11eb69dda7d17a065e05ff and later · before f2f65b28d802a667119147444ec2ae33eebf9a58affected · git
- 4bf5beef578e46393f11eb69dda7d17a065e05ff and later · before 715c263119fd1b918a9fcbd8a36ea5b604a46324affected · git
- 4bf5beef578e46393f11eb69dda7d17a065e05ff and later · before e15768e68820142077bbca402d8e902f64ade1b0affected · git
- 4bf5beef578e46393f11eb69dda7d17a065e05ff and later · before 496269d12072ecb219826485bdbec70c92a8eef5affected · git
- 4bf5beef578e46393f11eb69dda7d17a065e05ff and later · before d2a0cac10597068567d336e85fa3cbdbe8ca62bfaffected · git
- before 4.9not affected · semver
- 6.1.191 and later · up to and including 6.1.*not affected · semver
- 6.6.128 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	from 0	—
Debian:13	linux	before 6.12.85-1	6.12.85-1
Debian:14	linux	before 6.19.6-1	6.19.6-1
SUSE:Linux Micro 6.0	kernel-default	before 6.4.0-50.1	6.4.0-50.1
SUSE:Linux Micro 6.0	kernel-kvmsmall	before 6.4.0-50.1	6.4.0-50.1
SUSE:Linux Micro 6.0	kernel-rt	before 6.4.0-50.1	6.4.0-50.1
SUSE:Linux Micro 6.0	kernel-source	before 6.4.0-50.2	6.4.0-50.2
SUSE:Linux Micro 6.0	kernel-source-rt	before 6.4.0-50.2	6.4.0-50.2

Same product

linux: all records

Other highest-scoring records for the same primary product.

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CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now

Published before and after this one in the same product

← EarlierCVE-2026-43249May 6, 2026 · 9p/xen: protect xen_9pfs_front_free against concurrent calls
35Monitor
← EarlierCVE-2026-43250May 6, 2026 · usb: chipidea: udc: fix DMA and SG cleanup in _ep_nuke()
31Monitor
Later →CVE-2026-43258May 6, 2026 · alpha: fix user-space corruption during memory compaction
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	496269d12072ecb219826485bdbec70c92a8eef5	Vendor (CNA)
Linux Linux	69d9339c02eddfc2a345be7220651068a3684383	Vendor (CNA)
Linux Linux	715c263119fd1b918a9fcbd8a36ea5b604a46324	Vendor (CNA)
Linux Linux	d2a0cac10597068567d336e85fa3cbdbe8ca62bf	Vendor (CNA)
Linux Linux	e15768e68820142077bbca402d8e902f64ade1b0	Vendor (CNA)
Linux Linux	f2f65b28d802a667119147444ec2ae33eebf9a58	Vendor (CNA)
debian:linux	6.12.85-1 · Debian:13	Package registry (OSV)
suse:kernel-default	6.4.0-50.1 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-kvmsmall	6.4.0-50.1 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-rt	6.4.0-50.1 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-source	6.4.0-50.2 · SUSE:Linux Micro 6.0	Package registry (OSV)
suse:kernel-source-rt	6.4.0-50.2 · SUSE:Linux Micro 6.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).