GHSA-RWQH-F7G9-W86H
Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-64328"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-25T10:17:14Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix DMA fence leak\n\nIn ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc\u0027d, with the\nunderlying dma_fence later initialized by dma_fence_init(), which sets\nits kref counter to 1. Then, dma_resv_add_fence() gets a second\nreference, and a pointer to the ffs_dma_fence is passed as the\nusb_request\u0027s \"context\" field.\n\nThe dma-resv mechanism will manage the second reference, but the first\nreference is never properly released; the ffs_dmabuf_cleanup() function\ndecreases the reference count, but only to balance with the reference\ngrab in ffs_dmabuf_signal_done().\n\nThe code will then slowly leak memory as more ffs_dma_fence objects are\ncreated without being ever freed.\n\nAddress this issue by transferring ownership of the fence to the DMA\nreservation object, by calling dma_fence_put() right after\ndma_resv_add_fence(). The ffs_dma_fence then gets properly discarded\nafter being signalled.",
"id": "GHSA-rwqh-f7g9-w86h",
"modified": "2026-07-25T12:31:31Z",
"published": "2026-07-25T12:31:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64328"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0cae3d6109427c455bad0a18dfb3e2a91657e38a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b7475b2dce5e121e687280ba5732ccefe77ffd2f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/baa6b6068a3f2bf2ed525a1cb37975905dadc658"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e086c16962a1b0142e2675610e9c06fcfcd4c3a8"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
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Nomenclature
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