CVE-2026-23331 (GCVE-0-2026-23331)
Vulnerability from cvelistv5
Published
2026-03-25 10:27
Modified
2026-04-13 06:05
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected. Let's say we bind() an UDP socket to the wildcard address with a non-zero port, connect() it to an address, and disconnect it from the address. bind() sets SOCK_BINDPORT_LOCK on sk->sk_userlocks (but not SOCK_BINDADDR_LOCK), and connect() calls udp_lib_hash4() to put the socket into the 4-tuple hash table. Then, __udp_disconnect() calls sk->sk_prot->rehash(sk). It computes a new hash based on the wildcard address and moves the socket to a new slot in the 4-tuple hash table, leaving a garbage in the chain that no packet hits. Let's remove such a socket from 4-tuple hash table when disconnected. Note that udp_sk(sk)->udp_portaddr_hash needs to be udpated after udp_hash4_dec(hslot2) in udp_unhash4().
Impacted products
Vendor Product Version
Linux Linux Version: 78c91ae2c6deb5d236a5a93ff2995cdd05514380
Version: 78c91ae2c6deb5d236a5a93ff2995cdd05514380
Version: 78c91ae2c6deb5d236a5a93ff2995cdd05514380
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{
  "containers": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/udp.c"
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          "vendor": "Linux",
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              "version": "0",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected.\n\nLet\u0027s say we bind() an UDP socket to the wildcard address with a\nnon-zero port, connect() it to an address, and disconnect it from\nthe address.\n\nbind() sets SOCK_BINDPORT_LOCK on sk-\u003esk_userlocks (but not\nSOCK_BINDADDR_LOCK), and connect() calls udp_lib_hash4() to put\nthe socket into the 4-tuple hash table.\n\nThen, __udp_disconnect() calls sk-\u003esk_prot-\u003erehash(sk).\n\nIt computes a new hash based on the wildcard address and moves\nthe socket to a new slot in the 4-tuple hash table, leaving a\ngarbage in the chain that no packet hits.\n\nLet\u0027s remove such a socket from 4-tuple hash table when disconnected.\n\nNote that udp_sk(sk)-\u003eudp_portaddr_hash needs to be udpated after\nudp_hash4_dec(hslot2) in udp_unhash4()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T06:05:10.919Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b955350778b8715e1b7885179979b3a68221c0fb"
        },
        {
          "url": "https://git.kernel.org/stable/c/3b8f104880c104151f8c30f2f89df81fb59a286c"
        },
        {
          "url": "https://git.kernel.org/stable/c/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4"
        }
      ],
      "title": "udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected.",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23331",
    "datePublished": "2026-03-25T10:27:22.526Z",
    "dateReserved": "2026-01-13T15:37:45.996Z",
    "dateUpdated": "2026-04-13T06:05:10.919Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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