ipv6: mcast: fix RCU list diversion in ip6_mc_del1_src()

{
  "id": "2967adb52240a339d42817238856e87e1ea1dd748c9acdb5461017c75beefaea",
  "url": "https://osv.dev/vulnerability/CVE-2026-98102",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ipv6: mcast: fix RCU list diversion in ip6_mc_del1_src()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: fix RCU list diversion in ip6_mc_del1_src() When removing a source filter whose count reaches zero, ip6_mc_del1_src() unlinks psf from pmc->mca_sources. If the filter was previously active, the code moved psf directly into pmc->mca_tomb by updating psf->sf_next. Because pmc->mca_sources is traversed locklessly under RCU (e.g. by ipv6_chk_mcast_addr()), mutating psf->sf_next before a grace period elapses diverts concurrent readers to the tombstone list. Consequently, readers miss remaining active sources in pmc->mca_sources and improperly examine deleted tombstone entries. Fix this by allocating a new tombstone node for pmc->mca_tomb (as done in sf_setstate()) and retiring the original psf via kfree_rcu().",
    "evidence": "osv:CVE-2026-98102",
    "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": "unknown",
    "structured": {
      "id": "CVE-2026-98102",
      "aliases": [
        "CVE-2026-98102"
      ],
      "affected": [
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                  "fixed": "8d4fe5c13f5056faa6deb09a90e24a89f9ebfad4"
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              "type": "ECOSYSTEM",
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                  "introduced": "5.13.0"
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            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98102.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.174654747Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/4352737297b262e8367675c19a7dc6a9f53c97af",
        "https://git.kernel.org/stable/c/5149c60c406595b56fda0c6e9aae7fd287f636aa",
        "https://git.kernel.org/stable/c/8d4fe5c13f5056faa6deb09a90e24a89f9ebfad4",
        "https://git.kernel.org/stable/c/93b49239840b91313adbd77b8b52993eff2d08c1",
        "https://git.kernel.org/stable/c/c3343cd7ec8706c221e52b782f386b9af14a928a",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98102.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98102",
        "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-2026-98102.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98102",
        "evidence": "/id"
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    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505769,
  "published_at": "2026-09-25T10:35:53.332+00:00"
}