FKIE_CVE-2026-4747

Vulnerability from fkie_nvd - Published: 2026-03-26 07:16 - Updated: 2026-04-01 15:23
Severity ?
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet. This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow. Notably, this does not require the client to authenticate itself first. As kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel. In userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets. We are not aware of any such applications in the FreeBSD base system.
References
secteam@freebsd.orghttps://security.freebsd.org/advisories/FreeBSD-SA-26:08.rpcsec_gss.asc
af854a3a-2127-422b-91ae-364da2661108https://github.com/califio/publications/tree/main/MADBugs/CVE-2026-4747
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/califio/publications/blob/main/MADBugs/CVE-2026-4747/exploit.py
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet.  This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow.  Notably, this does not require the client to authenticate itself first.\n\nAs kgssapi.ko\u0027s RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel\u0027s NFS server while kgssapi.ko is loaded into the kernel.\n\nIn userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets.  We are not aware of any such applications in the FreeBSD base system."
    },
    {
      "lang": "es",
      "value": "Cada paquete de datos RPCSEC_GSS es validado por una rutina que verifica una firma en el paquete. Esta rutina copia una porci\u00f3n del paquete en un b\u00fafer de pila, pero no asegura que el b\u00fafer sea lo suficientemente grande, y un cliente malicioso puede desencadenar un desbordamiento de pila. En particular, esto no requiere que el cliente se autentique primero.\n\nDado que la implementaci\u00f3n RPCSEC_GSS de kgssapi.ko es vulnerable, la ejecuci\u00f3n remota de c\u00f3digo en el kernel es posible por un usuario autenticado que sea capaz de enviar paquetes al servidor NFS del kernel mientras kgssapi.ko est\u00e1 cargado en el kernel.\n\nEn el espacio de usuario, las aplicaciones que tienen librpcgss_sec cargado y ejecutan un servidor RPC son vulnerables a la ejecuci\u00f3n remota de c\u00f3digo desde cualquier cliente capaz de enviarle paquetes. No tenemos conocimiento de ninguna aplicaci\u00f3n de este tipo en el sistema base de FreeBSD."
    }
  ],
  "id": "CVE-2026-4747",
  "lastModified": "2026-04-01T15:23:23.797",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-26T07:16:20.670",
  "references": [
    {
      "source": "secteam@freebsd.org",
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:08.rpcsec_gss.asc"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://github.com/califio/publications/tree/main/MADBugs/CVE-2026-4747"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/califio/publications/blob/main/MADBugs/CVE-2026-4747/exploit.py"
    }
  ],
  "sourceIdentifier": "secteam@freebsd.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-121"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

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.