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CVE-2025-37749

Estado: ModificadaAlta (7.1)—

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

net: ppp: Add bound checking for skb data on ppp_sync_txmung

Ensure we have enough data in linear buffer from skb before accessing initial bytes. This prevents potential out-of-bounds accesses when processing short packets.

it is not safe to access data[2].

[pabeni@redhat.com: fixed subj typo]

Detalles técnicos trazas, registros y código del informe original
When ppp_sync_txmung receives an incoming package with an empty
payload:
(remote) gef➤  p *(struct pppoe_hdr *) (skb->head + skb->network_header)
$18 = {
	type = 0x1,
	ver = 0x1,
	code = 0x0,
	sid = 0x2,
        length = 0x0,
	tag = 0xffff8880371cdb96
}

from the skb struct (trimmed)
      tail = 0x16,
      end = 0x140,
      head = 0xffff88803346f400 "4",
      data = 0xffff88803346f416 ":\377",
      truesize = 0x380,
      len = 0x0,
      data_len = 0x0,
      mac_len = 0xe,
      hdr_len = 0x0,

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.

CVE-2025-37749: Acceso local (AV:L) sin interacción del usuario contra el kernel Linux. Out-of-bounds en ppp_sync_txmung permite lectura de memoria (C:H) y denegación de servicio (A:H) por crash del kernel. Se requieren privilegios locales (PR:L) para enviar paquetes PPP malformados.

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

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (2)

Debian — Debian LinuxLinux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
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          "value": "CWE-125"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ppp: Add bound checking for skb data on ppp_sync_txmung\n\nEnsure we have enough data in linear buffer from skb before accessing\ninitial bytes. This prevents potential out-of-bounds accesses\nwhen processing short packets.\n\nWhen ppp_sync_txmung receives an incoming package with an empty\npayload:\n(remote) gef➤  p *(struct pppoe_hdr *) (skb->head + skb->network_header)\n$18 = {\n\ttype = 0x1,\n\tver = 0x1,\n\tcode = 0x0,\n\tsid = 0x2,\n        length = 0x0,\n\ttag = 0xffff8880371cdb96\n}\n\nfrom the skb struct (trimmed)\n      tail = 0x16,\n      end = 0x140,\n      head = 0xffff88803346f400 \"4\",\n      data = 0xffff88803346f416 \":\\377\",\n      truesize = 0x380,\n      len = 0x0,\n      data_len = 0x0,\n      mac_len = 0xe,\n      hdr_len = 0x0,\n\nit is not safe to access data[2].\n\n[pabeni@redhat.com: fixed subj typo]"
    },
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      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: ppp: Se ha añadido la comprobación de los límites para datos de skb en ppp_sync_txmung. Se garantiza que haya suficientes datos en el búfer lineal de skb antes de acceder a los bytes iniciales. Esto evita posibles accesos fuera de los límites al procesar paquetes cortos. Cuando ppp_sync_txmung recibe un paquete entrante con un payload vacía: (remoto) gef? p *(struct pppoe_hdr *) (skb->head + skb->network_header) $18 = { type = 0x1, ver = 0x1, code = 0x0, sid = 0x2, length = 0x0, tag = 0xffff8880371cdb96 } de la estructura skb (recortada) tail = 0x16, end = 0x140, head = 0xffff88803346f400 \"4\", data = 0xffff88803346f416 \":\\377\", truesize = 0x380, len = 0x0, data_len = 0x0, mac_len = 0xe, hdr_len = 0x0, no es seguro acceder a los datos[2]. [pabeni@redhat.com: error tipográfico corregido]"
    }
  ],
  "lastModified": "2026-07-30T06:22:18.620",
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