CVE-2026-64327

Incorrect DMA direction via late endpoint initialization

Published Jul 25, 2026 · Updated Jul 25, 2026

Improper initialization in Linux Kernel 6.9 allows local users to trigger incorrect DMA directions through early FunctionFS ioctls. The ffs_data_got_descs() path records endpoint direction in eps_addrmap, but ffs_epfiles_create() left epfile->in at zero until ffs_func_eps_enable() ran. Reachability requires access to a FunctionFS endpoint before a USB host connects; published sources identify incorrect DMA direction but no resulting data disclosure, modification, or service interruption.

CVSS severity4.4
Medium
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

Improper initialization in Linux Kernel 6.9 allows local users to trigger incorrect DMA directions through early FunctionFS ioctls. The ffs_data_got_descs() path records endpoint direction in eps_addrmap, but ffs_epfiles_create() left epfile->in at zero until ffs_func_eps_enable() ran. Reachability requires access to a FunctionFS endpoint before a USB host connects; published sources identify incorrect DMA direction but no resulting data disclosure, modification, or service interruption.

The record

CVE
CVE-2026-64327
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
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 <82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b
  3. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <82cfd4739011bdc7e87b5d585703427e89ddfaa5
  4. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <9e04055ab5fc0470a0031ee6934739f9aa8f34a5
  5. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <f99f32ea9aa976afcbec20647ed33b50a52002c1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.9; version=7b07a2a7ca02a20124b552be96c5a56910795488 <82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b; version=7b07a2a7ca02a20124b552be96c5a56910795488 <82cfd4739011bdc7e87b5d585703427e89ddfaa5; version=7b07a2a7ca02a20124b552be96c5a56910795488 <9e04055ab5fc0470a0031ee6934739f9aa8f34a5; version=7b07a2a7ca02a20124b552be96c5a56910795488 <f99f32ea9aa976afcbec20647ed33b50a52002c1

Published CVSS scores

4.4Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

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

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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