Bug 2535120 (CVE-2026-89941)

Summary: CVE-2026-89941 kernel: iio: buffer: Make IIO DMA fence release RCU-safe
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's IIO (Industrial I/O) buffer component. The `iio_dma_fence` implementation incorrectly uses `kfree()` instead of `kfree_rcu()` for releasing DMA fence objects. This improper memory deallocation can lead to a use-after-free vulnerability. An attacker could potentially exploit this to cause a system crash (denial of service) or achieve arbitrary code execution.
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Description OSIDB Bzimport 2026-09-16 10:51:39 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iio: buffer: Make IIO DMA fence release RCU-safe

The `dma_fence` documentation states that if a custom release
implementation is provided, the `dma_fence` object must be freed in an
RCU-safe way. The current `iio_dma_fence` implementation uses `kfree()`,
which might result in a use-after-free.

Remove the custom `release` implementation. This makes the DMA fence core
fall back to `dma_fence_free()`, which calls `kfree_rcu()` on the fence.
This requires that the fence be the first member of `struct iio_dma_fence`.

Using the default release method for extended DMA fence structures is a
common pattern.
Comment 1 Keith Grant 2026-09-16 17:25:15 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89941.mbox