{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f"
            },
            {
              "fixed": "01b8569233e47693d6ff7efa96d9854c55f936fc"
            },
            {
              "fixed": "9c5fdffc5e1ce84403c58289ee72697051803bf7"
            },
            {
              "fixed": "f3e54f6a5e1681f83d13e8716bc92ef5ecf121d3"
            },
            {
              "fixed": "62e1c2741a4d923d9854efd5927a6212aad7a187"
            },
            {
              "fixed": "587a0accc2b4fccc5cf7baf0fe34e50efde51f9c"
            },
            {
              "fixed": "126a70bf1a08ddc9d79c471ebdaa2b08cfbab8df"
            },
            {
              "fixed": "ac1bb7fd45088d0db57a22ce7729f258ebd63cf5"
            },
            {
              "fixed": "dd9623f58ec702a07b2d67179d6fcea79c52231a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.10.0"
            },
            {
              "fixed": "5.10.265"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.216"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.183"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.151"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.103"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.44"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74518.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix list corruption in allocate_file_region_entries()\n\nallocate_file_region_entries() tops up resv-\u003eregion_cache with freshly\nallocated file_region descriptors.  The allocation uses GFP_KERNEL, so\nresv-\u003elock is dropped around it: the new entries are gathered on a\nstack-local list head, allocated_regions, and spliced into\nresv-\u003eregion_cache once the lock is re-acquired.\n\nThe splice used list_splice(), which moves the entries but does not\nre-initialize the source head, so allocated_regions is left pointing at an\nentry that now lives on resv-\u003eregion_cache.  The top-up runs in a while\nloop that re-checks the cache deficit after re-acquiring the lock.  For a\nshared mapping the resv_map is shared by every mapper of the hugetlbfs\ninode, so a concurrent region_chg()/region_add()/region_del() on the same\nresv_map can consume cache entries during the unlocked window and force a\nsecond iteration.  That iteration calls list_add() on the stale head and\ncorrupts the list; with CONFIG_DEBUG_LIST the __list_add_valid() check\ntrips:\n\n  list_add corruption. next-\u003eprev should be prev (ffffc900011ff7f8),\n  but was ffff88814c281460. (next=ffff88814c545640).\n  kernel BUG at lib/list_debug.c:31!\n   allocate_file_region_entries+0x191/0x420\n   region_chg+0x267/0x300\n   hugetlb_reserve_pages+0x387/0xc80\n   hugetlbfs_file_mmap+0x2ce/0x3f0\n   mmap_region+0x1348/0x1a80\n   do_mmap+0x85e/0xb90\n   vm_mmap_pgoff+0x18c/0x330\n   ksys_mmap_pgoff+0x2a1/0x3e0\n   do_syscall_64+0xd7/0x420\n\nWithout CONFIG_DEBUG_LIST the bad list_add() silently links a kernel-stack\naddress into resv-\u003eregion_cache, leading to later use-after-free.\n\nThis was observed as a real host panic on a dense KVM host where a QEMU\nguest-RAM hugetlbfs file was mapped MAP_SHARED by both QEMU and a separate\nSPDK/DPDK vhost-user target, generating concurrent region_* traffic on one\nshared resv_map.\n\nUse list_splice_init() so the source head is re-initialized empty after\neach splice, making the retry loop safe.",
  "id": "CVE-2026-74518",
  "modified": "2026-08-21T03:30:18.189035951Z",
  "published": "2026-08-15T12:27:37.480Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/01b8569233e47693d6ff7efa96d9854c55f936fc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/126a70bf1a08ddc9d79c471ebdaa2b08cfbab8df"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/587a0accc2b4fccc5cf7baf0fe34e50efde51f9c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/62e1c2741a4d923d9854efd5927a6212aad7a187"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c5fdffc5e1ce84403c58289ee72697051803bf7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ac1bb7fd45088d0db57a22ce7729f258ebd63cf5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dd9623f58ec702a07b2d67179d6fcea79c52231a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f3e54f6a5e1681f83d13e8716bc92ef5ecf121d3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74518.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74518"
    },
    {
      "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:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "mm/hugetlb: fix list corruption in allocate_file_region_entries()"
}