In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix DMA fence leak In ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc'd, with the underlying dma_fence later initialized by dma_fence_init(), which sets its kref counter to 1. Then, dma_resv_add_fence() gets a second reference, and a pointer to the ffs_dma_fence is passed as the usb_request's "context" field. The dma-resv mechanism will manage the second reference, but the first reference is never properly released; the ffs_dmabuf_cleanup() function decreases the reference count, but only to balance with the reference grab in ffs_dmabuf_signal_done(). The code will then slowly leak memory as more ffs_dma_fence objects are created without being ever freed. Address this issue by transferring ownership of the fence to the DMA reservation object, by calling dma_fence_put() right after dma_resv_add_fence(). The ffs_dma_fence then gets properly discarded after being signalled.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

References
Link Providers
https://git.kernel.org/stable/c/0cae3d6109427c455bad0a18dfb3e2a91657e38a cve-icon
https://git.kernel.org/stable/c/b7475b2dce5e121e687280ba5732ccefe77ffd2f cve-icon
https://git.kernel.org/stable/c/baa6b6068a3f2bf2ed525a1cb37975905dadc658 cve-icon
https://git.kernel.org/stable/c/e086c16962a1b0142e2675610e9c06fcfcd4c3a8 cve-icon
https://lore.kernel.org/linux-cve-announce/2026072513-CVE-2026-64328-f1c7@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-64328 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-64328 cve-icon
History

Wed, 29 Jul 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-772
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Sun, 26 Jul 2026 02:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-459

Sat, 25 Jul 2026 09:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix DMA fence leak In ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc'd, with the underlying dma_fence later initialized by dma_fence_init(), which sets its kref counter to 1. Then, dma_resv_add_fence() gets a second reference, and a pointer to the ffs_dma_fence is passed as the usb_request's "context" field. The dma-resv mechanism will manage the second reference, but the first reference is never properly released; the ffs_dmabuf_cleanup() function decreases the reference count, but only to balance with the reference grab in ffs_dmabuf_signal_done(). The code will then slowly leak memory as more ffs_dma_fence objects are created without being ever freed. Address this issue by transferring ownership of the fence to the DMA reservation object, by calling dma_fence_put() right after dma_resv_add_fence(). The ffs_dma_fence then gets properly discarded after being signalled.
Title usb: gadget: f_fs: Fix DMA fence leak
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-07-25T08:49:56.340Z

Updated: 2026-07-25T08:49:56.340Z

Reserved: 2026-07-19T15:36:31.780Z

Link: CVE-2026-64328

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-25T00:00:00Z

Links: CVE-2026-64328 - Bugzilla