{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "9330986c03006ab1d33d243b7cfe598a7a3c1baa"
            },
            {
              "fixed": "a6183bc683f97f4317f7e84939ca7fff37c5688b"
            },
            {
              "fixed": "80551bf8912c42d1e3d55eec6fa3c40f306c3de8"
            },
            {
              "fixed": "3b7a13eccfcf97714ffc1ca6aa663d66d4a30e29"
            },
            {
              "fixed": "272fcb4ba6fab678db0eb966dc81c4c804bef64a"
            },
            {
              "fixed": "dff481e12b3f127739f6a4ea7cef2c25dc12e056"
            },
            {
              "fixed": "11c1e836710dcba03e50454a4eedfdbaf8d3050e"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.188"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89579.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Harden bloom filter sizing and indexing on 32-bit kernels\n\nbloom_map_alloc() has two 32-bit-specific problems when the computed\nbitmap reaches the U32_MAX fallback case.\n\nFirst, BITS_TO_BYTES(U32_MAX) is evaluated with 32-bit arithmetic. The\naddition performed by DIV_ROUND_UP wraps, so the map allocates only the\nfixed-size bloom filter object while keeping bitset_mask == U32_MAX.\nSubsequent updates can then write past the allocated object.\n\nSecond, fixing only the allocation size is not sufficient. The bloom hash\nis a u32, but set_bit() takes a signed long bit number and x86 test_bit()\neventually feeds the index to variable_test_bit(long, ...). On 32-bit\nkernels, hashes in [0x80000000, U32_MAX] therefore become negative bit\noffsets. x86 bt/bts with a memory operand interpret those offsets relative\nto the supplied base, so a map with bitset_mask == U32_MAX can read or\nwrite before bloom-\u003ebitset even after allocating the full 512 MiB bitmap.\n\nKeep the U32_MAX fallback, but split each hash into a word pointer and an\nin-word bit number before calling test_bit() or set_bit(). The bitops\nargument is then always in [0, BITS_PER_LONG - 1], while BIT_WORD(h) still\nselects the intended word in the full bitmap.\n\nCompute the bitset size from (u64)bitset_mask + 1 before passing the final\nsize to bpf_map_area_alloc(). This fixes the original under-allocation and\nkeeps the allocated storage consistent with the addressable bitset.\n\nExploitation note: local privilege escalation is possible on a 32-bit x86\nkernel using the under-allocation bug from a binary with CAP_BPF.",
  "id": "CVE-2026-89579",
  "modified": "2026-09-16T03:30:13.963073404Z",
  "published": "2026-09-11T19:44:46.110Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/11c1e836710dcba03e50454a4eedfdbaf8d3050e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/272fcb4ba6fab678db0eb966dc81c4c804bef64a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3b7a13eccfcf97714ffc1ca6aa663d66d4a30e29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/80551bf8912c42d1e3d55eec6fa3c40f306c3de8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a6183bc683f97f4317f7e84939ca7fff37c5688b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dff481e12b3f127739f6a4ea7cef2c25dc12e056"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89579.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89579"
    },
    {
      "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": "bpf: Harden bloom filter sizing and indexing on 32-bit kernels"
}