Vulnerability-Lookup

FKIE_CVE-2026-23331

Vulnerability from fkie_nvd - Published: 2026-03-25 11:16 - Updated: 2026-04-23 21:13

Severity ?

5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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().

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3b8f104880c104151f8c30f2f89df81fb59a286c	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b955350778b8715e1b7885179979b3a68221c0fb	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.13
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0

JSON

To clipboard

{
  "configurations": [
    {
      "nodes": [
        {
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  "cveTags": [],
  "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()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nudp: Eliminar del hash el sk conectado auto-vinculado de la tabla hash de 4-tuplas cuando se desconecta.\n\nSupongamos que vinculamos (bind()) un socket UDP a la direcci\u00f3n comod\u00edn con un puerto no nulo, lo conectamos (connect()) a una direcci\u00f3n y lo desconectamos de la direcci\u00f3n.\n\nbind() establece SOCK_BINDPORT_LOCK en sk-\u0026gt;sk_userlocks (pero no SOCK_BINDADDR_LOCK), y connect() llama a udp_lib_hash4() para colocar el socket en la tabla hash de 4-tuplas.\n\nLuego, __udp_disconnect() llama a sk-\u0026gt;sk_prot-\u0026gt;rehash(sk).\n\nCalcula un nuevo hash basado en la direcci\u00f3n comod\u00edn y mueve el socket a una nueva ranura en la tabla hash de 4-tuplas, dejando basura en la cadena que ning\u00fan paquete alcanza.\n\nEliminemos dicho socket de la tabla hash de 4-tuplas cuando se desconecta.\n\nTenga en cuenta que udp_sk(sk)-\u0026gt;udp_portaddr_hash necesita ser actualizado despu\u00e9s de udp_hash4_dec(hslot2) en udp_unhash4()."
    }
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  "id": "CVE-2026-23331",
  "lastModified": "2026-04-23T21:13:28.780",
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
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        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
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  "published": "2026-03-25T11:16:30.510",
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}

CVE-2026-23331 (GCVE-0-2026-23331)

Vulnerability from cvelistv5 – Published: 2026-03-25 10:27 – Updated: 2026-04-13 06:05

Title

udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected.

Summary

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/b955350778b8715e1…
	https://git.kernel.org/stable/c/3b8f104880c104151…
	https://git.kernel.org/stable/c/6996a2d2d0a64808c…

Impacted products

Vendor

Product

Version

Linux

Affected: 78c91ae2c6deb5d236a5a93ff2995cdd05514380 , < b955350778b8715e1b7885179979b3a68221c0fb (git)
Affected: 78c91ae2c6deb5d236a5a93ff2995cdd05514380 , < 3b8f104880c104151f8c30f2f89df81fb59a286c (git)
Affected: 78c91ae2c6deb5d236a5a93ff2995cdd05514380 , < 6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4 (git)

Linux

Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.18.17 , ≤ 6.18.* (semver)
Unaffected: 6.19.7 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

FKIE_CVE-2026-23331

CVE-2026-23331 (GCVE-0-2026-23331)

Tags

Sightings

Nomenclature