{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": "153b5ecd29ed055562400bc17c91df3fd869b0ce",
              "status": "affected",
              "version": "de2080d41b5d584205e408d72021f0f335a046fc",
              "versionType": "git"
            },
            {
              "lessThan": "4a2fb2d12b87b43724230abb52a1440617c7b6cc",
              "status": "affected",
              "version": "de2080d41b5d584205e408d72021f0f335a046fc",
              "versionType": "git"
            },
            {
              "lessThan": "e78dcb1f7ec271449c54984dc90c62a5ba272de7",
              "status": "affected",
              "version": "de2080d41b5d584205e408d72021f0f335a046fc",
              "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": "4.0"
            },
            {
              "lessThan": "4.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\n\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\nfreed. However, for AIO operations, the kiocb cancel function was already\narmed and kiocb-\u003eprivate was set to `p`.\n\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\ncan occur when the cancellation handler accesses the freed pointer.\n\nTo securely fix this race condition, we must properly un-arm the\ncancellation. Invoking `kiocb-\u003eki_complete()` does exactly this by\nacquiring `ctx-\u003ectx_lock` and safely removing the kiocb from the active\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\ndiscover the kiocb, effectively closing the race window.\n\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\nconsumed and it should avoid attempting to complete the request again or\ntriggering subsequent completion handlers."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is in FunctionFS epfile AIO (`ffs_epfile_write_iter`/`read_iter` via `io_submit`/`io_cancel` on functionfs ep files), a local syscall path. `ffs_epfile_io()` can fail with `-EAGAIN` on `O_NONBLOCK` before any USB host is involved; this is the gadget userspace API, matching CVE-2024-36894/CVE-2026-63894 as Local rather than Physical.\nAC:L - The attacker controls both sides: one thread `io_submit`s AIO that fails after `kiocb_set_cancel_fn` (O_NONBLOCK `-EAGAIN`, halt, `-EFAULT`), while another calls `io_cancel`/`io_destroy`. The race between `kfree(p)` and `aio_remove_iocb` is freely retryable, so a race the attacker creates is AC:L.\nPR:L - FunctionFS mounts commonly use `uid=`/`gid=`/`fmode=` to delegate ep files to unprivileged gadget daemons (adbd/shell on Android, MTP, embedded USB services). Once mounted by init, those accounts can open ep files and issue AIO without init-namespace root.\nUI:N - The attacker performs `io_submit` and `io_cancel`/`io_destroy` on their own FunctionFS endpoint fds. No separate victim action is required beyond an already-deployed FunctionFS gadget.\nS:U - The use-after-free corrupts kernel heap (`ffs_io_data`) within the same host kernel security authority. This is ordinary local privilege escalation, not a VM escape or IOMMU/sandbox boundary cross.\nC:H - Use-after-free of `ffs_io_data`: `ffs_aio_cancel()` reads `kiocb-\u003eprivate` after `kfree`. Reclaim of that kmalloc object lets the attacker control `io_data-\u003eep`/`req` and leak kernel memory via UDC dequeue; UAFs are scored High for confidentiality.\nI:H - A reclaimed `ffs_io_data` yields attacker-controlled pointers passed to `usb_ep_dequeue()` from `ffs_aio_cancel`, providing a heap write and control-flow hijack primitive. Kernel UAFs are scored High for integrity.\nA:H - Dereferencing the freed `ffs_io_data` in `ffs_aio_cancel` causes kernel oops/panic even without a full exploit; any such crash is High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:41:58.245Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce"
        },
        {
          "url": "https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7"
        }
      ],
      "title": "usb: gadget: f_fs: Fix Use-After-Free in AIO error path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90044",
    "datePublished": "2026-09-16T10:33:41.695Z",
    "dateReserved": "2026-09-11T19:38:34.783Z",
    "dateUpdated": "2026-09-16T14:41:58.245Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-90044\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-16T11:17:17.660\",\"lastModified\":\"2026-09-16T15:18:27.100\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\\n\\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\\nfreed. However, for AIO operations, the kiocb cancel function was already\\narmed and kiocb-\u003eprivate was set to `p`.\\n\\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\\ncan occur when the cancellation handler accesses the freed pointer.\\n\\nTo securely fix this race condition, we must properly un-arm the\\ncancellation. Invoking `kiocb-\u003eki_complete()` does exactly this by\\nacquiring `ctx-\u003ectx_lock` and safely removing the kiocb from the active\\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\\ndiscover the kiocb, effectively closing the race window.\\n\\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\\nconsumed and it should avoid attempting to complete the request again or\\ntriggering subsequent completion handlers.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/usb/gadget/function/f_fs.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"de2080d41b5d584205e408d72021f0f335a046fc\",\"lessThan\":\"153b5ecd29ed055562400bc17c91df3fd869b0ce\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"de2080d41b5d584205e408d72021f0f335a046fc\",\"lessThan\":\"4a2fb2d12b87b43724230abb52a1440617c7b6cc\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"de2080d41b5d584205e408d72021f0f335a046fc\",\"lessThan\":\"e78dcb1f7ec271449c54984dc90c62a5ba272de7\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/usb/gadget/function/f_fs.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.51\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.5\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}