FKIE_CVE-2025-40123

Vulnerability from fkie_nvd - Published: 2025-11-12 11:15 - Updated: 2026-10-19 21:10
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Enforce expected_attach_type for tailcall compatibility Yinhao et al. recently reported: Our fuzzer tool discovered an uninitialized pointer issue in the bpf_prog_test_run_xdp() function within the Linux kernel's BPF subsystem. This leads to a NULL pointer dereference when a BPF program attempts to deference the txq member of struct xdp_buff object. The test initializes two programs of BPF_PROG_TYPE_XDP: progA acts as the entry point for bpf_prog_test_run_xdp() and its expected_attach_type can neither be of be BPF_XDP_DEVMAP nor BPF_XDP_CPUMAP. progA calls into a slot of a tailcall map it owns. progB's expected_attach_type must be BPF_XDP_DEVMAP to pass xdp_is_valid_access() validation. The program returns struct xdp_md's egress_ifindex, and the latter is only allowed to be accessed under mentioned expected_attach_type. progB is then inserted into the tailcall which progA calls. The underlying issue goes beyond XDP though. Another example are programs of type BPF_PROG_TYPE_CGROUP_SOCK_ADDR. sock_addr_is_valid_access() as well as sock_addr_func_proto() have different logic depending on the programs' expected_attach_type. Similarly, a program attached to BPF_CGROUP_INET4_GETPEERNAME should not be allowed doing a tailcall into a program which calls bpf_bind() out of BPF which is only enabled for BPF_CGROUP_INET4_CONNECT. In short, specifying expected_attach_type allows to open up additional functionality or restrictions beyond what the basic bpf_prog_type enables. The use of tailcalls must not violate these constraints. Fix it by enforcing expected_attach_type in __bpf_prog_map_compatible(). Note that we only enforce this for tailcall maps, but not for BPF devmaps or cpumaps: There, the programs are invoked through dev_map_bpf_prog_run*() and cpu_map_bpf_prog_run*() which set up a new environment / context and therefore these situations are not prone to this issue.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/08cb3dc9d2b44f153d0bcf2cb966e4a94b5d0f32
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4540aed51b12bc13364149bf95f6ecef013197c0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a99de19128aec0913f3d529f529fbbff5edfaff8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c1ad19b5d8e23123503dcaf2d4342e1b90b923ad
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dc4f348952173beb8ceb15be30b249276eccb605
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e53a59e7cee5c1605d1ed595933098c2b69108f9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f856c598080ba7ce1252867b8ecd6ad5bdaf9a6a
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf.h",
            "kernel/bpf/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e53a59e7cee5c1605d1ed595933098c2b69108f9",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            },
            {
              "lessThan": "dc4f348952173beb8ceb15be30b249276eccb605",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            },
            {
              "lessThan": "a99de19128aec0913f3d529f529fbbff5edfaff8",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            },
            {
              "lessThan": "08cb3dc9d2b44f153d0bcf2cb966e4a94b5d0f32",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            },
            {
              "lessThan": "f856c598080ba7ce1252867b8ecd6ad5bdaf9a6a",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            },
            {
              "lessThan": "c1ad19b5d8e23123503dcaf2d4342e1b90b923ad",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            },
            {
              "lessThan": "4540aed51b12bc13364149bf95f6ecef013197c0",
              "status": "affected",
              "version": "5e43f899b03a3492ce5fc44e8900becb04dae9c0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf.h",
            "kernel/bpf/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.17"
            },
            {
              "lessThan": "4.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.156",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Enforce expected_attach_type for tailcall compatibility\n\nYinhao et al. recently reported:\n\n  Our fuzzer tool discovered an uninitialized pointer issue in the\n  bpf_prog_test_run_xdp() function within the Linux kernel\u0027s BPF subsystem.\n  This leads to a NULL pointer dereference when a BPF program attempts to\n  deference the txq member of struct xdp_buff object.\n\nThe test initializes two programs of BPF_PROG_TYPE_XDP: progA acts as the\nentry point for bpf_prog_test_run_xdp() and its expected_attach_type can\nneither be of be BPF_XDP_DEVMAP nor BPF_XDP_CPUMAP. progA calls into a slot\nof a tailcall map it owns. progB\u0027s expected_attach_type must be BPF_XDP_DEVMAP\nto pass xdp_is_valid_access() validation. The program returns struct xdp_md\u0027s\negress_ifindex, and the latter is only allowed to be accessed under mentioned\nexpected_attach_type. progB is then inserted into the tailcall which progA\ncalls.\n\nThe underlying issue goes beyond XDP though. Another example are programs\nof type BPF_PROG_TYPE_CGROUP_SOCK_ADDR. sock_addr_is_valid_access() as well\nas sock_addr_func_proto() have different logic depending on the programs\u0027\nexpected_attach_type. Similarly, a program attached to BPF_CGROUP_INET4_GETPEERNAME\nshould not be allowed doing a tailcall into a program which calls bpf_bind()\nout of BPF which is only enabled for BPF_CGROUP_INET4_CONNECT.\n\nIn short, specifying expected_attach_type allows to open up additional\nfunctionality or restrictions beyond what the basic bpf_prog_type enables.\nThe use of tailcalls must not violate these constraints. Fix it by enforcing\nexpected_attach_type in __bpf_prog_map_compatible().\n\nNote that we only enforce this for tailcall maps, but not for BPF devmaps or\ncpumaps: There, the programs are invoked through dev_map_bpf_prog_run*() and\ncpu_map_bpf_prog_run*() which set up a new environment / context and therefore\nthese situations are not prone to this issue."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nbpf: Hacer cumplir expected_attach_type para la compatibilidad de tailcall\n\nYinhao et al. informaron recientemente:\n\n  Nuestra herramienta de fuzzing descubri\u00f3 un problema de puntero no\n  inicializado en la funci\u00f3n bpf_prog_test_run_xdp() dentro del subsistema\n  BPF del kernel de Linux. Esto lleva a una desreferencia de puntero NULL\n  cuando un programa BPF intenta desreferenciar el miembro txq del objeto\n  struct xdp_buff.\n\nLa prueba inicializa dos programas de BPF_PROG_TYPE_XDP: progA act\u00faa como\npunto de entrada para bpf_prog_test_run_xdp() y su expected_attach_type no\npuede ser ni BPF_XDP_DEVMAP ni BPF_XDP_CPUMAP. progA llama a una ranura de\nun mapa de tailcall que posee. El expected_attach_type de progB debe ser\nBPF_XDP_DEVMAP para pasar la validaci\u00f3n de xdp_is_valid_access(). El\nprograma devuelve el egress_ifindex de struct xdp_md, y este \u00faltimo solo\npuede ser accedido bajo el expected_attach_type mencionado. progB se inserta\nentonces en el tailcall al que llama progA.\n\nSin embargo, el problema subyacente va m\u00e1s all\u00e1 de XDP. Otro ejemplo son los\nprogramas de tipo BPF_PROG_TYPE_CGROUP_SOCK_ADDR. sock_addr_is_valid_access()\nas\u00ed como sock_addr_func_proto() tienen l\u00f3gica diferente dependiendo del\nexpected_attach_type de los programas. De manera similar, un programa\nadjunto a BPF_CGROUP_INET4_GETPEERNAME no deber\u00eda permit\u00edrsele hacer un\ntailcall a un programa que llama a bpf_bind() fuera de BPF, lo cual solo\nest\u00e1 habilitado para BPF_CGROUP_INET4_CONNECT.\n\nEn resumen, especificar expected_attach_type permite habilitar funcionalidad\no restricciones adicionales m\u00e1s all\u00e1 de lo que permite el bpf_prog_type\nb\u00e1sico. El uso de tailcalls no debe violar estas restricciones. Se soluciona\nhaciendo cumplir expected_attach_type en __bpf_prog_map_compatible().\n\nTenga en cuenta que solo hacemos cumplir esto para los mapas de tailcall,\npero no para los devmaps o cpumaps de BPF: All\u00ed, los programas se invocan a\ntrav\u00e9s de dev_map_bpf_prog_run*() y cpu_map_bpf_prog_run*() que configuran\nun nuevo entorno/contexto y, por lo tanto, estas situaciones no son\npropensas a este problema."
    }
  ],
  "id": "CVE-2025-40123",
  "lastModified": "2026-10-19T21:10:00.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-40123",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-15T21:57:04.979824Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-11-12T11:15:41.807",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/08cb3dc9d2b44f153d0bcf2cb966e4a94b5d0f32"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4540aed51b12bc13364149bf95f6ecef013197c0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a99de19128aec0913f3d529f529fbbff5edfaff8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c1ad19b5d8e23123503dcaf2d4342e1b90b923ad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dc4f348952173beb8ceb15be30b249276eccb605"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e53a59e7cee5c1605d1ed595933098c2b69108f9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f856c598080ba7ce1252867b8ecd6ad5bdaf9a6a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}



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