Local crash via mismatched DMA free size
Published Apr 24, 2026 · Updated Apr 24, 2026
Incorrect DMA deallocation in the Linux kernel brcmsmac driver allows local users to crash affected systems during wireless DMA teardown. In drivers/net/wireless/broadcom/brcm80211/brcmsmac/dma.c, dma_alloc_consistent() can align the requested size and store the adjusted value in alloced, but dma_free_coherent() receives the original size instead of the allocation size. Exploitation requires local low-privileged access and an affected Broadcom brcmsmac wireless path; the reported consequence is loss of availability, not data disclosure or modification.
Summary
What happened
Incorrect DMA deallocation in the Linux kernel brcmsmac driver allows local users to crash affected systems during wireless DMA teardown. In drivers/net/wireless/broadcom/brcm80211/brcmsmac/dma.c, dma_alloc_consistent() can align the requested size and store the adjusted value in alloced, but dma_free_coherent() receives the original size instead of the allocation size. Exploitation requires local low-privileged access and an affected Broadcom brcmsmac wireless path; the reported consequence is loss of availability, not data disclosure or modification.
The record
- CVE
- CVE-2026-31661
- Published
- Apr 24, 2026
- Updated
- Apr 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 24, 2026CVE publishedPublication date reported by the CVE source.
- Apr 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=3.2
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <01f1330d3d1bee07e0c42d40cc48b7be8b6dad84
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <0f87777b74bcce29b966ec42d9aa8f9edd9b1667
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <12cd7632757a54ce586e36040210b1a738a0fc53
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <3c204a0fd079fa7a867151a47d830ad1c2db5177
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <4bf41c2731a0549e21f66180ff780b1e036639ab
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <77263f053963dea9f3962505ac0c768853d7dc59
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <b27fa888e4a426a3bcf6f6ab24701d888d9bf5aa
- Affected versionversion=5b435de0d786869c95d1962121af0d7df2542009 <f449676bab54fea1440775c8c915dadb323fe015
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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