CVE-2026-64327

usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks

MEDIUM
5.5
CVSS Score
Published: July 25, 2026 at 08:49 AM UTC
Updated: September 4, 2026 at 03:36 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.18.396.19 ≤ v < 7.1.46.9 ≤ v < 6.12.966.9 ≤ v < 6.18.396.9 ≤ v < 7.1.46.9 ≤ v < 7.27.2 rc17.2 rc27b07a2a7ca02a20124b552be96c5a56910795488
Vendor states this is fixed in 82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b (fixed)
Vendor states this is fixed in 82cfd4739011bdc7e87b5d585703427e89ddfaa5 (fixed)
Vendor states this is fixed in 9e04055ab5fc0470a0031ee6934739f9aa8f34a5 (fixed)
Vendor states this is fixed in f99f32ea9aa976afcbec20647ed33b50a52002c1 (fixed)
Vendor states this is fixed in 6.12.96 (unaffected)
Vendor states this is fixed in 6.18.39 (unaffected)
Vendor states this is fixed in 6.9 (unaffected)
Vendor states this is fixed in 7.1.4 (unaffected)
Vendor states this is fixed in 7.2 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-noinfo

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