Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Local access with low privileges required to use the USB gadget DMA interface; impact is kernel memory exhaustion only, with no confidentiality or integrity effect.
AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
6DescriptionNVD
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.
AnalysisAI
Kernel memory leak in the Linux USB gadget FunctionFS (f_fs) subsystem allows a local low-privileged user to slowly exhaust kernel memory by repeatedly triggering DMA buffer transfers via the ffs_dmabuf_transfer() code path. Affected kernels span from the commit introducing DMA buffer sharing (7b07a2a7ca02) through versions prior to 6.12.96, 7.1.4, and 7.2-rc3. The root cause is a missing dma_fence_put() call after dma_resv_add_fence(), leaving the initial kref permanently outstanding and causing ffs_dma_fence objects to accumulate without ever being freed. No public exploit has been identified at time of analysis.
Technical ContextAI
The vulnerability resides in the Linux kernel's USB gadget FunctionFS (f_fs) subsystem within the DMA buffer sharing implementation in ffs_dmabuf_transfer(). DMA fences (struct dma_fence) use kernel reference counting (kref) to govern object lifetimes: dma_fence_init() sets kref to 1, and dma_resv_add_fence() acquires a second reference on behalf of the DMA reservation object. The bug, classified as CWE-401 (Missing Release of Memory after Effective Lifetime), is that the original reference is never dropped after ownership is transferred to the reservation object. The ffs_dmabuf_cleanup() function only balances the grab performed by ffs_dmabuf_signal_done(), so the initial reference remains permanently outstanding. The minimal one-line fix - inserting dma_fence_put() immediately after dma_resv_add_fence() - correctly transfers ownership so the reservation object becomes the sole holder and releases the fence upon signaling. CPE: cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*.
RemediationAI
Upgrade to a patched Linux kernel version: 6.12.96, 7.1.4, or 7.2-rc3 or later, per the upstream fix commits at git.kernel.org/stable/c/b7475b2dce5e121e687280ba5732ccefe77ffd2f, git.kernel.org/stable/c/0cae3d6109427c455bad0a18dfb3e2a91657e38a, git.kernel.org/stable/c/baa6b6068a3f2bf2ed525a1cb37975905dadc658, and git.kernel.org/stable/c/e086c16962a1b0142e2675610e9c06fcfcd4c3a8. On systems where patching is not immediately possible, the attack surface can be fully eliminated by preventing the usb_f_fs kernel module from loading (blacklist usb_f_fs in /etc/modprobe.d/) or by restricting access to the FunctionFS mount point, with the trade-off of disabling USB gadget functionality. Systems that do not use USB gadget mode at all require no action beyond routine kernel maintenance.
Same weakness CWE-401 – Memory Leak
View allVendor StatusVendor
SUSE
Severity: Moderate| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
| SUSE Linux Enterprise Desktop 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP7 | Not-Affected |
| SUSE Linux Enterprise High Availability Extension 15 SP7 | Not-Affected |
| SUSE Linux Enterprise High Availability Extension 15 SP7 | Not-Affected |
| SUSE Linux Enterprise High Availability Extension 16.0 | Not-Affected |
| SUSE Linux Enterprise High Availability Extension 16.0 | Not-Affected |
| SUSE Linux Enterprise High Availability Extension 16.1 | Not-Affected |
| SUSE Linux Enterprise High Availability Extension 16.1 | Not-Affected |
| SUSE Linux Enterprise Live Patching 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Live Patching 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Micro 5.3 | Not-Affected |
| SUSE Linux Enterprise Micro 5.3 | Not-Affected |
| SUSE Linux Enterprise Micro 5.3 | Not-Affected |
| SUSE Linux Enterprise Micro 5.3 | Not-Affected |
| SUSE Linux Enterprise Micro 5.4 | Not-Affected |
| SUSE Linux Enterprise Micro 5.4 | Not-Affected |
| SUSE Linux Enterprise Micro 5.4 | Not-Affected |
| SUSE Linux Enterprise Micro 5.4 | Not-Affected |
| SUSE Linux Enterprise Micro 5.5 | Not-Affected |
| SUSE Linux Enterprise Micro 5.5 | Not-Affected |
| SUSE Linux Enterprise Micro 5.5 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Legacy 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Legacy 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Public Cloud 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Public Cloud 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server 16.0 | Not-Affected |
| SUSE Linux Enterprise Server 16.0 | Affected |
| SUSE Linux Enterprise Server 16.1 | Not-Affected |
| SUSE Linux Enterprise Server 16.1 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Not-Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Not-Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Not-Affected |
| SUSE Linux Enterprise Workstation Extension 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Workstation Extension 15 SP7 | Not-Affected |
| SUSE Linux Micro 6.0 | Not-Affected |
| SUSE Linux Micro 6.0 | Not-Affected |
| SUSE Linux Micro 6.0 | Not-Affected |
| SUSE Linux Micro 6.1 | Not-Affected |
| SUSE Linux Micro 6.1 | Not-Affected |
| SUSE Linux Micro 6.1 | Not-Affected |
| SUSE Linux Micro 6.2 | Not-Affected |
| SUSE Linux Micro 6.2 | Affected |
| SUSE Linux Micro Extras 6.0 | Not-Affected |
| SUSE Linux Micro Extras 6.0 | Not-Affected |
| SUSE Linux Micro Extras 6.0 | Not-Affected |
| SUSE Linux Micro Extras 6.1 | Not-Affected |
| SUSE Linux Micro Extras 6.1 | Not-Affected |
| SUSE Real Time Module 15 SP7 | Not-Affected |
| openSUSE Leap 16.0 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Live Patching 12 SP5 | Not-Affected |
| SUSE Linux Enterprise Live Patching 12 SP5 | Not-Affected |
| SUSE Linux Enterprise Live Patching 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Live Patching 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Live Patching 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Live Patching 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Not-Affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Not-Affected |
| SUSE Linux Enterprise Server 12 SP5 | Not-Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Not-Affected |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Not-Affected |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Not-Affected |
| SUSE CaaS Platform 4.0 | Not-Affected |
| SUSE Enterprise Storage 6 | Not-Affected |
| SUSE Enterprise Storage 7 | Not-Affected |
| SUSE Enterprise Storage 7.1 | Not-Affected |
| SUSE Linux Enterprise Desktop 11 SP4 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP6 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Not-Affected |
| SUSE Linux Enterprise Micro 5.0 | Not-Affected |
| SUSE Linux Enterprise Micro 5.1 | Not-Affected |
| SUSE Linux Enterprise Micro 5.2 | Not-Affected |
| SUSE Linux Enterprise Micro 5.2 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server 11 SP4 | Not-Affected |
| SUSE Linux Enterprise Server 11 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Not-Affected |
| SUSE Manager Proxy 4.0 | Not-Affected |
| SUSE Manager Proxy 4.1 | Not-Affected |
| SUSE Manager Proxy 4.2 | Not-Affected |
| SUSE Manager Proxy 4.3 | Not-Affected |
| SUSE Manager Proxy LTS 4.3 | Not-Affected |
| SUSE Manager Retail Branch Server 4.0 | Not-Affected |
| SUSE Manager Retail Branch Server 4.1 | Not-Affected |
| SUSE Manager Retail Branch Server 4.2 | Not-Affected |
| SUSE Manager Retail Branch Server 4.3 | Not-Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | Not-Affected |
| SUSE Manager Server 4.0 | Not-Affected |
| SUSE Manager Server 4.1 | Not-Affected |
| SUSE Manager Server 4.2 | Not-Affected |
| SUSE Manager Server 4.3 | Not-Affected |
| SUSE Manager Server LTS 4.3 | Not-Affected |
| SUSE Real Time Module 15 SP4 | Not-Affected |
| SUSE Real Time Module 15 SP5 | Not-Affected |
| openSUSE Leap 15.3 | Not-Affected |
| openSUSE Leap 15.4 | Not-Affected |
| openSUSE Leap 15.4 | Not-Affected |
| openSUSE Leap 15.5 | Not-Affected |
| openSUSE Leap 15.5 | Not-Affected |
| openSUSE Leap 15.6 | Not-Affected |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-48872
GHSA-rwqh-f7g9-w86h