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CVE-2026-64327
usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks When parsing endpoint descriptors, ffs_data_got_descs() generates the eps_addrmap which contains the endpoint direction. However, epfile->in was previously only populated in ffs_func_eps_enable() which executes upon USB host connection. As a result, early userspace ioctls like FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see epfile->in as 0, leading to incorrect DMA directions. By moving the initialization to ffs_epfiles_create(), epfile->in is accurate before userspace opens the endpoint files.

Details
INFO

Published Date :

July 25, 2026, 10:17 a.m.

Last Modified :

Aug. 17, 2026, 5:17 a.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-64327 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Ensure endpoint file structures are initialized correctly for accurate direction checks.
  • Update the Linux kernel to include the fix.
  • Verify endpoint file initialization logic.
  • Test userspace ioctls before host connection.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-64327.

URL Resource
https://git.kernel.org/stable/c/82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b
https://git.kernel.org/stable/c/82cfd4739011bdc7e87b5d585703427e89ddfaa5
https://git.kernel.org/stable/c/9e04055ab5fc0470a0031ee6934739f9aa8f34a5
https://git.kernel.org/stable/c/f99f32ea9aa976afcbec20647ed33b50a52002c1
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-64327 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-64327 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-64327 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-64327 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 2026

    Action Type Old Value New Value
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '9e04055ab5fc0470a0031ee6934739f9aa8f34a5', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': 'f99f32ea9aa976afcbec20647ed33b50a52002c1', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '82cfd4739011bdc7e87b5d585703427e89ddfaa5', 'versionType': 'git'}], 'programFiles': ['drivers/usb/gadget/function/f_fs.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.9'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.9', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/usb/gadget/function/f_fs.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '9e04055ab5fc0470a0031ee6934739f9aa8f34a5', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': 'f99f32ea9aa976afcbec20647ed33b50a52002c1', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '82cfd4739011bdc7e87b5d585703427e89ddfaa5', 'versionType': 'git'}], 'programFiles': ['drivers/usb/gadget/function/f_fs.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.9'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.9', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/usb/gadget/function/f_fs.c'], 'defaultStatus': 'affected'}]
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 25, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '9e04055ab5fc0470a0031ee6934739f9aa8f34a5', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': 'f99f32ea9aa976afcbec20647ed33b50a52002c1', 'versionType': 'git'}, {'status': 'affected', 'version': '7b07a2a7ca02a20124b552be96c5a56910795488', 'lessThan': '82cfd4739011bdc7e87b5d585703427e89ddfaa5', 'versionType': 'git'}], 'programFiles': ['drivers/usb/gadget/function/f_fs.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.9'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.9', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc3', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/usb/gadget/function/f_fs.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks When parsing endpoint descriptors, ffs_data_got_descs() generates the eps_addrmap which contains the endpoint direction. However, epfile->in was previously only populated in ffs_func_eps_enable() which executes upon USB host connection. As a result, early userspace ioctls like FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see epfile->in as 0, leading to incorrect DMA directions. By moving the initialization to ffs_epfiles_create(), epfile->in is accurate before userspace opens the endpoint files.
    Added Reference https://git.kernel.org/stable/c/82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b
    Added Reference https://git.kernel.org/stable/c/82cfd4739011bdc7e87b5d585703427e89ddfaa5
    Added Reference https://git.kernel.org/stable/c/9e04055ab5fc0470a0031ee6934739f9aa8f34a5
    Added Reference https://git.kernel.org/stable/c/f99f32ea9aa976afcbec20647ed33b50a52002c1
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
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