Bug 2536376 (CVE-2026-93121) - CVE-2026-93121 kernel: usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths
Summary: CVE-2026-93121 kernel: usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_tra...
Keywords:
Status: NEW
Alias: CVE-2026-93121
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: 2026-09-17 17:35 UTC by OSIDB Bzimport
Modified: 2026-10-20 11:39 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-17 17:35:37 UTC
In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths

The error paths for endpoint-disabled (ESHUTDOWN) and request-allocation
failure (ENOMEM) in ffs_dmabuf_transfer() jump to err_fence_put which
calls dma_fence_put() on the fence. However, at that point the fence has
only been kmalloc'd — dma_fence_init() has not been called yet, so the
refcount and the fence ops are uninitialized. Calling dma_fence_put() on
such an object leads to undefined behavior.

Use kfree() instead, since the fence is just a plain allocation at this
stage, and rename the label to err_fence_free to reflect the actual
cleanup action.


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