CVE-2026-43253: linux Improper Locking
Vulnerability summary
CVE-2026-43253 is a high (CVSS 7.5) Improper Locking vulnerability in linux. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 40.8% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 25 · Related 25Timeline
- 06-05-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.49%
Chance of exploitation in the next 30 days
Percentile
41%
Versus all other CVEs
30-day change
+0.15 pp
From 0.34% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-667Improper LockingThe product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
- CWE-833DeadlockThe product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock.
Affected systems
Ubuntu157 products
- linuxAll versions (No fix recorded) | < 6.8.0-134.134
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 6.8.0-1060.63
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 4bf5beef578e46393f11eb69dda7d17a065e05ff, < f2f65b28d802a667119147444ec2ae33eebf9a58 | ≥ 4bf5beef578e46393f11eb69dda7d17a065e05ff, < 715c263119fd1b918a9fcbd8a36ea5b604a46324 | ≥ 4bf5beef578e46393f11eb69dda7d17a065e05ff, < e15768e68820142077bbca402d8e902f64ade1b0 | ≥ 4bf5beef578e46393f11eb69dda7d17a065e05ff, < 496269d12072ecb219826485bdbec70c92a8eef5 | ≥ 4bf5beef578e46393f11eb69dda7d17a065e05ff, < d2a0cac10597068567d336e85fa3cbdbe8ca62bf | 4.9
- linux_kernel≥ 4.9, < 6.6.128 | ≥ 6.7, < 6.12.75 | ≥ 6.13, < 6.18.16 | ≥ 6.19, < 6.19.6
Debian1 product
- linuxAll versions (No fix recorded) | < 6.12.85-1 | < 6.19.6-1
3 vendors · 160 products
