{
  "id": "CVE-2026-98303",
  "url": "https://spydr.io/cve/CVE-2026-98303",
  "published": "2026-10-06T09:18:21.370Z",
  "modified": "2026-10-06T09:18:21.370Z",
  "score": null,
  "severity": null,
  "cvss_version": null,
  "vector": null,
  "score_source": null,
  "epss": 0.0018,
  "epss_percentile": 0.06922,
  "exploited": false,
  "kev": null,
  "ssvc_exploitation": null,
  "vendors": [
    "Linux"
  ],
  "products": [
    "Linux"
  ],
  "cwes": [],
  "description": "In the Linux kernel, the following vulnerability has been resolved: ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup When the forward output route cannot be used in icmp_route_lookup(), it enters the \"reverse path\" and calls ip_route_input() on fl4_dec.daddr, the original packet's source address. ip_route_input() only returns an error for truly invalid packets. For unreachable addresses it will succeed and return an input route whose dst.output is set to ip_rt_bug(). The existing check only rejects RTN_LOCAL routes, so the RTN_UNREACHABLE route types can still be returned and later used for output, syzkaller triggering a WARN_ON_ONCE() in ip_rt_bug() as bellow: ------------[ cut here ]------------ WARNING: net/ipv4/route.c:1273 at ip_rt_bug+0x14/0x20 RIP: 0010:ip_rt_bug+0x14/0x20 Call Trace: ip_push_pending_frames+0xfa/0x100 __icmp_send+0x905/0xf10 ip_options_compile+0xc0/0xd0 ip_rcv_finish_core+0x321/0xae0 ip_rcv+0x1de/0x260 __netif_receive_skb_one_core+0x11a/0x130 netif_receive_skb+0x7b/0x260 tun_get_user+0x11bf/0x1c10 ------------[ cut here ]------------ Reject input route that is RTN_UNREACHABLE to fix it. The net warning is only printed for RTN_LOCAL, as RTN_UNREACHABLE is not the result of a race condition.",
  "status": "Received",
  "score_type": null,
  "scores": {
    "cvss_v40": null,
    "cvss_v31": null,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/06083cea4a3b95f5ebc85312f97d7086e6c9e782",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/1af2d87964d87ba7626d96928d68c09158b5a223",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/2998147b59c9df0a51477c7a6b3d1f0ba3127dd4",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/83aa83f81a8fec30ff5372dee60b2f0561bcb2ca",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/cac69c50716c712ef0114837c9427da66066124c",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/fda3000147dc96c75ba162f680bec0a9fecf3037",
      "tags": []
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98303",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}