Bug 2507071 (CVE-2026-64327) - CVE-2026-64327 kernel: usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks
Summary: CVE-2026-64327 kernel: usb: gadget: f_fs: Initialize epfile->in early to fix ...
Keywords:
Status: NEW
Alias: CVE-2026-64327
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-25 10:03 UTC by OSIDB Bzimport
Modified: 2026-07-30 05:56 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-07-25 10:03:28 UTC
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.


Note You need to log in before you can comment on or make changes to this bug.