CVE-2026-93121
usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths
Description
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.
INFO
Published Date :
Sept. 17, 2026, 5:18 p.m.
Last Modified :
Sept. 18, 2026, 6:18 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Replace dma_fence_put() with kfree() in error paths.
- Rename label to err_fence_free.
- Apply the provided kernel patch.
- Update the Linux kernel.
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-2026-93121.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-93121 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-2026-93121
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).
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The following list is the news that have been mention
CVE-2026-93121 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-93121 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.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 17, 2026
Action Type Old Value New Value Added Description 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/93xxx/CVE-2026-93121.json">CVE-2026-93121</a> Added Reference https://git.kernel.org/stable/c/58952c83dfe6ea3294a74734d2d1018c1120779a Added Reference https://git.kernel.org/stable/c/5fd8baacc7dc477df9cac61b45491840247a9b1e Added Reference https://git.kernel.org/stable/c/621707dc67c9846fd876d7579ec951d92aa033f1 Added Reference https://git.kernel.org/stable/c/be539138d9a187af3b884525a395db10797c64f1