vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()

{
  "id": "9565e16e6b2718d88c50b212822df22a491d0cb52138cf9b568d5f8e434f24dd",
  "url": "https://osv.dev/vulnerability/CVE-2026-98122",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del() vxlan_mdb_is_valid_source(), which validates MDBE_ATTR_SOURCE and every MDBE_ATTR_SRC_LIST member, accepts the all-zeros address. A source list is only accepted on a (*, G) entry, whose source is the all-zeros address, and for each member of the list an (S, G) entry is derived from it by substituting the source. Entries are keyed by a plain memcmp() of struct vxlan_mdb_entry_key, so if MDBE_ATTR_SOURCE is present and holds the all-zeros address and the source list holds it as well, the derived (S, G) key is byte-identical to the (*, G) key and resolves to the same entry. Omitting MDBE_ATTR_SOURCE is not equivalent, as the key is then left with a zero address family. vxlan_mdb_remote_src_del() removes the forwarding entry of a source before freeing the source entry: vxlan_mdb_remote_src_fwd_del(vxlan, group, remote, &ent->addr); vxlan_mdb_remote_src_entry_del(ent); With the keys aliased, the first call deletes the remote of the entry that owns 'ent' instead of a separate (S, G) entry, and frees 'ent'. The second call then runs on the freed entry, and its hlist_del() reads ->pprev and ->next out of it and writes through them. Adding the (*, G) entry with NLM_F_REPLACE and no source list marks the all-zeros source for deletion and reaches this from the sweep at the end of vxlan_mdb_remote_srcs_replace(). BUG: KASAN: slab-use-after-free in __vxlan_mdb_a",
    "evidence": "osv:CVE-2026-98122",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.158",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.111",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.53",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-98122",
      "aliases": [
        "CVE-2026-98122"
      ],
      "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": [
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              "type": "GIT",
              "events": [
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                {
                  "fixed": "069d5527bb0f229e528fa88c6b72f15060c373f2"
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                {
                  "fixed": "e12c903fd13c6261b98ca18d8f70ac26e739e2f8"
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                {
                  "fixed": "74e2a56c82209b0335b53e25f19f9b0590e2483d"
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                  "fixed": "71203a41d6fa2fa0ea2f3a7541987958bd3694fd"
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                {
                  "fixed": "4aa61c88b4e292e10abdfd791334b8272108d68a"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98122.json"
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        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.4.0"
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                {
                  "fixed": "6.6.158"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.7.0"
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                {
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                  "introduced": "6.13.0"
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                {
                  "fixed": "6.18.53"
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
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                {
                  "fixed": "7.2.7"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98122.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.762507500Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/069d5527bb0f229e528fa88c6b72f15060c373f2",
        "https://git.kernel.org/stable/c/4aa61c88b4e292e10abdfd791334b8272108d68a",
        "https://git.kernel.org/stable/c/71203a41d6fa2fa0ea2f3a7541987958bd3694fd",
        "https://git.kernel.org/stable/c/74e2a56c82209b0335b53e25f19f9b0590e2483d",
        "https://git.kernel.org/stable/c/e12c903fd13c6261b98ca18d8f70ac26e739e2f8",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98122.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98122",
        "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-2026-98122.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98122",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517149,
  "published_at": "2026-09-25T10:36:05.369+00:00"
}