CVE-2026-64328

Kernel-memory exhaustion via unreleased DMA fence references

Published Jul 25, 2026 · Updated Jul 25, 2026

Memory leak in Linux Kernel 6.9 allows local users to consume kernel memory through repeated USB FunctionFS DMA-BUF transfers. The ffs_dmabuf_transfer() path gives dma_resv_add_fence() a second reference but never releases the initial dma_fence_init() reference, so each completed request leaves its ffs_dma_fence allocated. Reachability requires local access to a configured USB FunctionFS gadget and repeated DMA-BUF transfers; the documented consequence is gradual kernel-memory exhaustion rather than data access or code execution.

CVSS severity3.3
Low
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in Linux Kernel 6.9 allows local users to consume kernel memory through repeated USB FunctionFS DMA-BUF transfers. The ffs_dmabuf_transfer() path gives dma_resv_add_fence() a second reference but never releases the initial dma_fence_init() reference, so each completed request leaves its ffs_dma_fence allocated. Reachability requires local access to a configured USB FunctionFS gadget and repeated DMA-BUF transfers; the documented consequence is gradual kernel-memory exhaustion rather than data access or code execution.

The record

CVE
CVE-2026-64328
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.9
  2. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <0cae3d6109427c455bad0a18dfb3e2a91657e38a
  3. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <b7475b2dce5e121e687280ba5732ccefe77ffd2f
  4. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <baa6b6068a3f2bf2ed525a1cb37975905dadc658
  5. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <e086c16962a1b0142e2675610e9c06fcfcd4c3a8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.9; version=7b07a2a7ca02a20124b552be96c5a56910795488 <0cae3d6109427c455bad0a18dfb3e2a91657e38a; version=7b07a2a7ca02a20124b552be96c5a56910795488 <b7475b2dce5e121e687280ba5732ccefe77ffd2f; version=7b07a2a7ca02a20124b552be96c5a56910795488 <baa6b6068a3f2bf2ed525a1cb37975905dadc658; version=7b07a2a7ca02a20124b552be96c5a56910795488 <e086c16962a1b0142e2675610e9c06fcfcd4c3a8

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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