net: bridge: mdb: restart port group walk after deletion

{
  "id": "72bccb0aa3055773c364f473487a09da25cb6e6e6c138a8d4574a6da3ebc16fc",
  "url": "https://osv.dev/vulnerability/CVE-2026-98487",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: bridge: mdb: restart port group walk after deletion",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: bridge: mdb: restart port group walk after deletion br_mdb_flush_pgs() keeps a pointer-to-pointer cursor while walking mp->ports. br_multicast_del_pg() can re-enter the same MDB entry through br_multicast_sg_del_exclude_ports() and unlink other port groups. If the cursor points into one of those groups, the next iteration dereferences a stale cursor and can leave mp->ports pointing at freed memory. A following RTM_GETMDB exposes the dangling pointer: BUG: KASAN: slab-use-after-free in br_mdb_dump Read of size 8 br_mdb_dump rtnl_mdb_dump rtnl_dumpit netlink_dump Reset the cursor to mp->ports after every deletion. The deletion removes at least the selected group, so the restarted walk always makes progress.",
    "evidence": "osv:CVE-2026-98487",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.112",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.55",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-98487",
      "aliases": [
        "CVE-2026-98487"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a6acb535afb2a3b688a7858f05b61f0433e480d5"
                },
                {
                  "fixed": "46ec55855c972504258c371677ac039ba20e5d12"
                },
                {
                  "fixed": "ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe"
                },
                {
                  "fixed": "fe2a42789c12eb7c5d3a42191e2cc735a6c35ead"
                },
                {
                  "fixed": "ab1404ac81154a89fb61ac50ae9a04cd8d4834dc"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98487.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.8.0"
                },
                {
                  "fixed": "6.12.112"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.55"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.9"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98487.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.663897823Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/46ec55855c972504258c371677ac039ba20e5d12",
        "https://git.kernel.org/stable/c/ab1404ac81154a89fb61ac50ae9a04cd8d4834dc",
        "https://git.kernel.org/stable/c/ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe",
        "https://git.kernel.org/stable/c/fe2a42789c12eb7c5d3a42191e2cc735a6c35ead",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98487.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98487",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98487.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98487",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497795,
  "published_at": "2026-10-18T15:16:04.746+00:00"
}