{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix ip_rt_bug race in icmp_route_lookup reverse path\n\nicmp_route_lookup() performs multiple route lookups to find a suitable\nroute for sending ICMP error messages, with special handling for XFRM\n(IPsec) policies.\n\nThe lookup sequence is:\n1. First, lookup output route for ICMP reply (dst = original src)\n2. Pass through xfrm_lookup() for policy check\n3. If blocked (-EPERM) or dst is not local, enter \"reverse path\"\n4. In reverse path, call xfrm_decode_session_reverse() to get fl4_dec\n   which reverses the original packet\u0027s flow (saddr\u003c-\u003edaddr swapped)\n5. If fl4_dec.saddr is local (we are the original destination), use\n   __ip_route_output_key() for output route lookup\n6. If fl4_dec.saddr is NOT local (we are a forwarding node), use\n   ip_route_input() to simulate the reverse packet\u0027s input path\n7. Finally, pass rt2 through xfrm_lookup() with XFRM_LOOKUP_ICMP flag\n\nThe bug occurs in step 6: ip_route_input() is called with fl4_dec.daddr\n(original packet\u0027s source) as destination. If this address becomes local\nbetween the initial check and ip_route_input() call (e.g., due to\nconcurrent \"ip addr add\"), ip_route_input() returns a LOCAL route with\ndst.output set to ip_rt_bug.\n\nThis route is then used for ICMP output, causing dst_output() to call\nip_rt_bug(), triggering a WARN_ON:\n\n ------------[ cut here ]------------\n WARNING: net/ipv4/route.c:1275 at ip_rt_bug+0x21/0x30, CPU#1\n Call Trace:\n  \u003cTASK\u003e\n  ip_push_pending_frames+0x202/0x240\n  icmp_push_reply+0x30d/0x430\n  __icmp_send+0x1149/0x24f0\n  ip_options_compile+0xa2/0xd0\n  ip_rcv_finish_core+0x829/0x1950\n  ip_rcv+0x2d7/0x420\n  __netif_receive_skb_one_core+0x185/0x1f0\n  netif_receive_skb+0x90/0x450\n  tun_get_user+0x3413/0x3fb0\n  tun_chr_write_iter+0xe4/0x220\n  ...\n\nFix this by checking rt2-\u003ert_type after ip_route_input(). If it\u0027s\nRTN_LOCAL, the route cannot be used for output, so treat it as an error.\n\nThe reproducer requires kernel modification to widen the race window,\nmaking it unsuitable as a selftest. It is available at:\n\n  https://gist.github.com/mrpre/eae853b72ac6a750f5d45d64ddac1e81"
    }
  ],
  "id": "CVE-2026-45905",
  "lastModified": "2026-05-27T14:48:31.480",
  "metrics": {},
  "published": "2026-05-27T14:17:04.993",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1c9ef28f643cce34a6a6c36c8f4d6d60a60db7e1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2c1f59005da9dd4b07b26984fd719e36557dc57c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/423ce12d10b426709489d6b84fdaa6d2f31c5652"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/81b84de32bb27ae1ae2eb9acf0420e9d0d14bf00"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9a95ec9144eeff1fc6fbcc21b677e322c6f1430b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b04061f89ffc6168e7ec3c71d0086ec3c3797228"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-45905"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:04Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix ip_rt_bug race in icmp_route_lookup reverse path\n\nicmp_route_lookup() performs multiple route lookups to find a suitable\nroute for sending ICMP error messages, with special handling for XFRM\n(IPsec) policies.\n\nThe lookup sequence is:\n1. First, lookup output route for ICMP reply (dst = original src)\n2. Pass through xfrm_lookup() for policy check\n3. If blocked (-EPERM) or dst is not local, enter \"reverse path\"\n4. In reverse path, call xfrm_decode_session_reverse() to get fl4_dec\n   which reverses the original packet\u0027s flow (saddr\u003c-\u003edaddr swapped)\n5. If fl4_dec.saddr is local (we are the original destination), use\n   __ip_route_output_key() for output route lookup\n6. If fl4_dec.saddr is NOT local (we are a forwarding node), use\n   ip_route_input() to simulate the reverse packet\u0027s input path\n7. Finally, pass rt2 through xfrm_lookup() with XFRM_LOOKUP_ICMP flag\n\nThe bug occurs in step 6: ip_route_input() is called with fl4_dec.daddr\n(original packet\u0027s source) as destination. If this address becomes local\nbetween the initial check and ip_route_input() call (e.g., due to\nconcurrent \"ip addr add\"), ip_route_input() returns a LOCAL route with\ndst.output set to ip_rt_bug.\n\nThis route is then used for ICMP output, causing dst_output() to call\nip_rt_bug(), triggering a WARN_ON:\n\n ------------[ cut here ]------------\n WARNING: net/ipv4/route.c:1275 at ip_rt_bug+0x21/0x30, CPU#1\n Call Trace:\n  \u003cTASK\u003e\n  ip_push_pending_frames+0x202/0x240\n  icmp_push_reply+0x30d/0x430\n  __icmp_send+0x1149/0x24f0\n  ip_options_compile+0xa2/0xd0\n  ip_rcv_finish_core+0x829/0x1950\n  ip_rcv+0x2d7/0x420\n  __netif_receive_skb_one_core+0x185/0x1f0\n  netif_receive_skb+0x90/0x450\n  tun_get_user+0x3413/0x3fb0\n  tun_chr_write_iter+0xe4/0x220\n  ...\n\nFix this by checking rt2-\u003ert_type after ip_route_input(). If it\u0027s\nRTN_LOCAL, the route cannot be used for output, so treat it as an error.\n\nThe reproducer requires kernel modification to widen the race window,\nmaking it unsuitable as a selftest. It is available at:\n\n  https://gist.github.com/mrpre/eae853b72ac6a750f5d45d64ddac1e81",
  "id": "GHSA-qfvj-mcf4-fgpg",
  "modified": "2026-05-27T15:33:15Z",
  "published": "2026-05-27T15:33:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45905"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c9ef28f643cce34a6a6c36c8f4d6d60a60db7e1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2c1f59005da9dd4b07b26984fd719e36557dc57c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/423ce12d10b426709489d6b84fdaa6d2f31c5652"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81b84de32bb27ae1ae2eb9acf0420e9d0d14bf00"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9a95ec9144eeff1fc6fbcc21b677e322c6f1430b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b04061f89ffc6168e7ec3c71d0086ec3c3797228"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}