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CVE-2026-31538

Estado: AnalizadaAlta (7.5)—

In the Linux kernel, the following vulnerability has been resolved:

smb: server: make use of smbdirect_socket.recv_io.credits.available

The logic off managing recv credits by counting posted recv_io and granted credits is racy.

That's because the peer might already consumed a credit, but between receiving the incoming recv at the hardware and processing the completion in the 'recv_done' functions we likely have a window where we grant credits, which don't really exist.

So we better have a decicated counter for the available credits, which will be incremented when we posted new recv buffers and drained when we grant the credits to the peer.

Leer descripción completaMostrar menos

This fixes regression Namjae reported with the 6.18 release.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vector de red sin privilegios (AV:N, PR:N) sugiere T1190. Condición de carrera en gestión de créditos SMBDirect causa agotamiento de disponibilidad (A:H). Impacto primario es denegación de servicio por depleción de recursos.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-31538",
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    "cvssMetricV31": [
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
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          "confidentialityImpact": "NONE"
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  "published": "2026-04-24T15:16:27.740",
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      "source": "nvd@nist.gov",
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: server: make use of smbdirect_socket.recv_io.credits.available\n\nThe logic off managing recv credits by counting posted recv_io and\ngranted credits is racy.\n\nThat's because the peer might already consumed a credit,\nbut between receiving the incoming recv at the hardware\nand processing the completion in the 'recv_done' functions\nwe likely have a window where we grant credits, which\ndon't really exist.\n\nSo we better have a decicated counter for the\navailable credits, which will be incremented\nwhen we posted new recv buffers and drained when\nwe grant the credits to the peer.\n\nThis fixes regression Namjae reported with\nthe 6.18 release."
    }
  ],
  "lastModified": "2026-06-17T10:33:56.200",
  "configurations": [
    {
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}