FKIE_CVE-2026-64328

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-25 10:17
Severity
Summary
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.
Impacted products
Vendor Product Version

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_fs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b7475b2dce5e121e687280ba5732ccefe77ffd2f",
              "status": "affected",
              "version": "7b07a2a7ca02a20124b552be96c5a56910795488",
              "versionType": "git"
            },
            {
              "lessThan": "e086c16962a1b0142e2675610e9c06fcfcd4c3a8",
              "status": "affected",
              "version": "7b07a2a7ca02a20124b552be96c5a56910795488",
              "versionType": "git"
            },
            {
              "lessThan": "0cae3d6109427c455bad0a18dfb3e2a91657e38a",
              "status": "affected",
              "version": "7b07a2a7ca02a20124b552be96c5a56910795488",
              "versionType": "git"
            },
            {
              "lessThan": "baa6b6068a3f2bf2ed525a1cb37975905dadc658",
              "status": "affected",
              "version": "7b07a2a7ca02a20124b552be96c5a56910795488",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_fs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2026-64328",
  "lastModified": "2026-07-25T10:17:14.430",
  "metrics": {},
  "published": "2026-07-25T10:17:14.430",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0cae3d6109427c455bad0a18dfb3e2a91657e38a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b7475b2dce5e121e687280ba5732ccefe77ffd2f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/baa6b6068a3f2bf2ed525a1cb37975905dadc658"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e086c16962a1b0142e2675610e9c06fcfcd4c3a8"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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