FKIE_CVE-2026-23254

Vulnerability from fkie_nvd - Published: 2026-03-18 18:16 - Updated: 2026-03-19 13:25
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net: gro: fix outer network offset The udp GRO complete stage assumes that all the packets inserted the RX have the `encapsulation` flag zeroed. Such assumption is not true, as a few H/W NICs can set such flag when H/W offloading the checksum for an UDP encapsulated traffic, the tun driver can inject GSO packets with UDP encapsulation and the problematic layout can also be created via a veth based setup. Due to the above, in the problematic scenarios, udp4_gro_complete() uses the wrong network offset (inner instead of outer) to compute the outer UDP header pseudo checksum, leading to csum validation errors later on in packet processing. Address the issue always clearing the encapsulation flag at GRO completion time. Such flag will be set again as needed for encapsulated packets by udp_gro_complete().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2e5edb69e5d0e23ef248c56fc977039268c77a7b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5c2c3c38be396257a6a2e55bd601a12bb9781507
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9d40a85138568696387ef04cd004c64612a70874
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b83557bc6f560433fe5d727e241069f8db5ba709
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: gro: fix outer network offset\n\nThe udp GRO complete stage assumes that all the packets inserted the RX\nhave the `encapsulation` flag zeroed. Such assumption is not true, as a\nfew H/W NICs can set such flag when H/W offloading the checksum for\nan UDP encapsulated traffic, the tun driver can inject GSO packets with\nUDP encapsulation and the problematic layout can also be created via\na veth based setup.\n\nDue to the above, in the problematic scenarios, udp4_gro_complete() uses\nthe wrong network offset (inner instead of outer) to compute the outer\nUDP header pseudo checksum, leading to csum validation errors later on\nin packet processing.\n\nAddress the issue always clearing the encapsulation flag at GRO completion\ntime. Such flag will be set again as needed for encapsulated packets by\nudp_gro_complete()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: gro: corregir desplazamiento de red externo\n\nLa etapa de completado de GRO de UDP asume que todos los paquetes insertados en el RX tienen el indicador \u0027encapsulation\u0027 puesto a cero. Dicha suposici\u00f3n no es cierta, ya que algunas NIC de H/W pueden establecer dicho indicador al descargar el checksum por H/W para un tr\u00e1fico UDP encapsulado, el controlador tun puede inyectar paquetes GSO con encapsulaci\u00f3n UDP y la disposici\u00f3n problem\u00e1tica tambi\u00e9n puede crearse a trav\u00e9s de una configuraci\u00f3n basada en veth.\n\nDebido a lo anterior, en los escenarios problem\u00e1ticos, udp4_gro_complete() utiliza el desplazamiento de red incorrecto (interno en lugar de externo) para calcular el pseudo checksum del encabezado UDP externo, lo que lleva a errores de validaci\u00f3n de csum m\u00e1s adelante en el procesamiento de paquetes.\n\nAbordar el problema siempre borrando el indicador de encapsulaci\u00f3n en el momento de completado de GRO. Dicho indicador se establecer\u00e1 de nuevo seg\u00fan sea necesario para paquetes encapsulados por udp_gro_complete()."
    }
  ],
  "id": "CVE-2026-23254",
  "lastModified": "2026-03-19T13:25:00.570",
  "metrics": {},
  "published": "2026-03-18T18:16:23.530",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2e5edb69e5d0e23ef248c56fc977039268c77a7b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5c2c3c38be396257a6a2e55bd601a12bb9781507"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9d40a85138568696387ef04cd004c64612a70874"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b83557bc6f560433fe5d727e241069f8db5ba709"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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