CVE-2026-63894

Kernel memory corruption via stale DMABUF request

Published Jul 19, 2026 · Updated Jul 19, 2026

Use-after-free in Linux Kernel 6.9 allows local users with FunctionFS device access to corrupt kernel memory through a DMABUF race. ffs_epfile_dmabuf_io_complete() frees a completed usb_request without clearing priv->req, so detach or close can pass that stale pointer to usb_ep_dequeue(). The path requires local access to a FunctionFS endpoint device node, which defaults to root ownership but can be delegated to a less-privileged gadget daemon; USB hosts cannot reach it.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel 6.9 allows local users with FunctionFS device access to corrupt kernel memory through a DMABUF race. ffs_epfile_dmabuf_io_complete() frees a completed usb_request without clearing priv->req, so detach or close can pass that stale pointer to usb_ep_dequeue(). The path requires local access to a FunctionFS endpoint device node, which defaults to root ownership but can be delegated to a less-privileged gadget daemon; USB hosts cannot reach it.

The record

CVE
CVE-2026-63894
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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 <2796646f6d892c1eb6818c7ca41fdfa12568e8d1
  3. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <552dae28dbeb5f7c4fafcda43962dc46569f58a0
  4. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <c7d421123b98d5e9c1c84bd9957aba36f1cbb4ca
  5. Affected versionversion=7b07a2a7ca02a20124b552be96c5a56910795488 <c872d8a065b3b499ce4c3ad168b5d34b68524f66

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.9; version=7b07a2a7ca02a20124b552be96c5a56910795488 <2796646f6d892c1eb6818c7ca41fdfa12568e8d1; version=7b07a2a7ca02a20124b552be96c5a56910795488 <552dae28dbeb5f7c4fafcda43962dc46569f58a0; version=7b07a2a7ca02a20124b552be96c5a56910795488 <c7d421123b98d5e9c1c84bd9957aba36f1cbb4ca; version=7b07a2a7ca02a20124b552be96c5a56910795488 <c872d8a065b3b499ce4c3ad168b5d34b68524f66

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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