GHSA-JC3M-QG79-3244
Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-04-23 21:31In 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().
{
"affected": [],
"aliases": [
"CVE-2026-23331"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-03-25T11:16:30Z",
"severity": "MODERATE"
},
"details": "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().",
"id": "GHSA-jc3m-qg79-3244",
"modified": "2026-04-23T21:31:17Z",
"published": "2026-03-25T12:30:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23331"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3b8f104880c104151f8c30f2f89df81fb59a286c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b955350778b8715e1b7885179979b3a68221c0fb"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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