Vulnerability in Linux kernel (CVE-2026-89940)
Summary
Vulnerability in Linux kernel (CVE-2026-89940). Successful exploitation can lead to full system takeover. Exploitable via iio_dma_fence.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
iio: buffer: Tie IIO dma fence lock lifetime to the fence
The iio_dma_fence implementation currently uses a lock embedded in the
iio_dmabuf_priv. But the iio_dma_fence can outlive the
iio_dmabuf_priv, which can cause a use-after-free.
Tie the lifetime of the lock to the lifetime of the fence by embedding them
in the same struct.
We can't just hold a reference to the iio_dmabuf_priv from the
iio_dma_fence since iio_buffer_dmabuf_release() might sleep and the
fence release callback is not allowed to sleep.
Note that the dma_fence framework now has an internal lock that gets used
when the passing NULL for lock in dma_fence_init(), but in order to
allow this patch to be backportable use an external lock.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-89940 has been found in Linux kernel.
Attackers can target a specific entry point like iio_dma_fence over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89940" on the vendor's site.
CVE-2026-89940 (Linux kernel) — CVSS v3 7.8
Attack vector: local / no user interaction
Attack surface: iio_dma_fence / iio_dmabuf_priv / dma_fence / NULL
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel. Attackers reach the vulnerable code path via iio_dma_fence.
Check the vendor advisory for the affected versions of Linux kernel. Attack surface: iio_dma_fence / iio_dmabuf_priv / dma_fence / NULL.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com