{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "b91accafbb1031b80d22ad83576877ff2f8b4774"
            },
            {
              "fixed": "9dc84ba4be5bbeb29ee49efe6cea2cb32c461424"
            },
            {
              "fixed": "d16a702ca7d29c0b7a9b509339d1b044a1cadb32"
            },
            {
              "fixed": "a13ef1adbc62085b21b546b07b0be7e2fbf52150"
            },
            {
              "fixed": "0d4a646d7f87ea3625fafe387043fddc6a2f5e7f"
            },
            {
              "fixed": "72c6aa8e0d74eab91b8694cde97dec088c248fee"
            },
            {
              "fixed": "9edefd4c56bee3fe331e0355d1f10a533134999d"
            },
            {
              "fixed": "f187dc5a4c4846ffa07d9bda6e760837ed005574"
            },
            {
              "fixed": "af791d295737ea6b6ff2c8d8488462a49c14af01"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.15.0"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.96"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.39"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64496.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\niio: event: Fix event FIFO reset race\n\n`iio_event_getfd()` creates the event file descriptor with\n`anon_inode_getfd()`, which allocates a new fd, creates the anonymous\nfile and installs it in the process fd table before returning to the\ncaller.\n\nThe IIO code resets the event FIFO after `anon_inode_getfd()` has returned,\nbut before `IIO_GET_EVENT_FD_IOCTL` has copied the fd number to userspace.\nBut since fd tables are shared between threads, another thread can guess\nthe newly allocated fd number and issue a `read()` on it as soon as the fd\nhas been installed.\n\nThis means the `kfifo_to_user()` in `iio_event_chrdev_read()` can run in\nparallel with the `kfifo_reset_out()` in `iio_event_getfd()`.\n\nThe kfifo documentation says that `kfifo_reset_out()` is only safe when it\nis called from the reader thread and there is only one concurrent reader.\nOtherwise it is dangerous and must be handled in the same way as\n`kfifo_reset()`.\n\nIf that happens, `kfifo_to_user()` can advance the FIFO `out` index based\non state from before the reset, after the reset has already moved the `out`\nindex to the current `in` index. That can leave the FIFO with an `out`\nindex past the `in` index. A later `read()` can then see an underflowed\nFIFO length and copy more data than the event FIFO buffer contains. This\ncan result in an out-of-bounds read and leak adjacent kernel memory to\nuserspace.\n\nMove the FIFO reset before `anon_inode_getfd()`. At that point the event fd is\nmarked busy, but the new fd has not been installed yet, so userspace cannot\naccess it while the FIFO is reset.",
  "id": "CVE-2026-64496",
  "modified": "2026-08-18T03:31:16.803814998Z",
  "published": "2026-07-25T08:51:53.194Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d4a646d7f87ea3625fafe387043fddc6a2f5e7f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/72c6aa8e0d74eab91b8694cde97dec088c248fee"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9dc84ba4be5bbeb29ee49efe6cea2cb32c461424"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9edefd4c56bee3fe331e0355d1f10a533134999d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a13ef1adbc62085b21b546b07b0be7e2fbf52150"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/af791d295737ea6b6ff2c8d8488462a49c14af01"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d16a702ca7d29c0b7a9b509339d1b044a1cadb32"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f187dc5a4c4846ffa07d9bda6e760837ed005574"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64496.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64496"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "iio: event: Fix event FIFO reset race"
}