genetlink: fix genl_bind() invoking bind() after -EPERM

{
  "id": "7cbf7ff7a95054f101c31379f035dd5bd063bf0103a3d116659594def78bcdd5",
  "url": "https://osv.dev/vulnerability/CVE-2025-39926",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "genetlink: fix genl_bind() invoking bind() after -EPERM",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: genetlink: fix genl_bind() invoking bind() after -EPERM Per family bind/unbind callbacks were introduced to allow families to track multicast group consumer presence, e.g. to start or stop producing events depending on listeners. However, in genl_bind() the bind() callback was invoked even if capability checks failed and ret was set to -EPERM. This means that callbacks could run on behalf of unauthorized callers while the syscall still returned failure to user space. Fix this by only invoking bind() after \"if (ret) break;\" check i.e. after permission checks have succeeded.",
    "evidence": "osv:CVE-2025-39926",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.48",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.16.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-39926",
      "aliases": [
        "CVE-2025-39926"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "3de21a8990d3c2cc507e9cc4ed00f36358d5b93e"
                },
                {
                  "fixed": "98c9d884047a3051c203708914a874dece3cbe54"
                },
                {
                  "fixed": "8858c1e9405906c09589d7c336f04058ea198207"
                },
                {
                  "fixed": "1dbfb0363224f6da56f6655d596dc5097308d6f5"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39926.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.9.0"
                },
                {
                  "fixed": "6.12.48"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.16.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39926.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.857936861Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1dbfb0363224f6da56f6655d596dc5097308d6f5",
        "https://git.kernel.org/stable/c/8858c1e9405906c09589d7c336f04058ea198207",
        "https://git.kernel.org/stable/c/98c9d884047a3051c203708914a874dece3cbe54",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39926.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-39926",
        "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/2025/39xxx/CVE-2025-39926.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-39926",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518519,
  "published_at": "2025-10-01T08:07:13.883+00:00"
}