ipvs: fix NULL deref in ip_vs_add_service error path

{
  "id": "9dec1c274f396e2321d4ae34260ae84f5c2e4f1ccf73634e531af8cf61472514",
  "url": "https://osv.dev/vulnerability/CVE-2026-43086",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ipvs: fix NULL deref in ip_vs_add_service error path",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ipvs: fix NULL deref in ip_vs_add_service error path When ip_vs_bind_scheduler() succeeds in ip_vs_add_service(), the local variable sched is set to NULL. If ip_vs_start_estimator() subsequently fails, the out_err cleanup calls ip_vs_unbind_scheduler(svc, sched) with sched == NULL. ip_vs_unbind_scheduler() passes the cur_sched NULL check (because svc->scheduler was set by the successful bind) but then dereferences the NULL sched parameter at sched->done_service, causing a kernel panic at offset 0x30 from NULL. Oops: general protection fault, [..] [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] RIP: 0010:ip_vs_unbind_scheduler (net/netfilter/ipvs/ip_vs_sched.c:69) Call Trace: ip_vs_add_service.isra.0 (net/netfilter/ipvs/ip_vs_ctl.c:1500) do_ip_vs_set_ctl (net/netfilter/ipvs/ip_vs_ctl.c:2809) nf_setsockopt (net/netfilter/nf_sockopt.c:102) [..] Fix by simply not clearing the local sched variable after a successful bind. ip_vs_unbind_scheduler() already detects whether a scheduler is installed via svc->scheduler, and keeping sched non-NULL ensures the error path passes the correct pointer to both ip_vs_unbind_scheduler() and ip_vs_scheduler_put(). While the bug is older, the problem popups in more recent kernels (6.2), when the new error path is taken after the ip_vs_start_estimator() call.",
    "evidence": "osv:CVE-2026-43086",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.136",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.83",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.24",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.14",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-43086",
      "aliases": [
        "CVE-2026-43086"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "705dd34440812735ece298eb5bc153fde9544d42"
                },
                {
                  "fixed": "730663352c9178f33fcf5929f4a37c1f1ca5a693"
                },
                {
                  "fixed": "4039959315008888dd53c37674d33351817a5166"
                },
                {
                  "fixed": "a32dabacee111cea083ddd57a03635672e1bff29"
                },
                {
                  "fixed": "c2ddbe577e2ebf63f2d8fb15cdc7503af70f3e94"
                },
                {
                  "fixed": "9a91797e61d286805ae10a92cc48959c30800556"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43086.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.136"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
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                {
                  "fixed": "6.12.83"
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.24"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "6.19.14"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43086.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.159773029Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/4039959315008888dd53c37674d33351817a5166",
        "https://git.kernel.org/stable/c/730663352c9178f33fcf5929f4a37c1f1ca5a693",
        "https://git.kernel.org/stable/c/9a91797e61d286805ae10a92cc48959c30800556",
        "https://git.kernel.org/stable/c/a32dabacee111cea083ddd57a03635672e1bff29",
        "https://git.kernel.org/stable/c/c2ddbe577e2ebf63f2d8fb15cdc7503af70f3e94",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43086.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43086",
        "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/2026/43xxx/CVE-2026-43086.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-43086",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 501223,
  "published_at": "2026-05-06T07:40:20.631+00:00"
}