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CVE-2025-40143

Estado: AplazadaSin puntuar—

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

bpf: dont report verifier bug for missing bpf_scc_visit on speculative path

Syzbot generated a program that triggers a verifier_bug() call in maybe_exit_scc(). maybe_exit_scc() assumes that, when called for a state with insn_idx in some SCC, there should be an instance of struct bpf_scc_visit allocated for that SCC. Turns out the assumption does not hold for speculative execution paths. See example in the next patch.

maybe_scc_exit() is called from update_branch_counts() for states that reach branch count of zero, meaning that path exploration for a particular path is finished.

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Path exploration can finish in one of three ways: a. Verification error is found. In this case, update_branch_counts() is called only for non-speculative paths. b. Top level BPF_EXIT is reached. Such instructions are never a part of an SCC, so compute_scc_callchain() in maybe_scc_exit() will return false, and maybe_scc_exit() will return early. c. A checkpoint is reached and matched. Checkpoints are created by is_state_visited(), which calls maybe_enter_scc(), which allocates bpf_scc_visit instances for checkpoints within SCCs.

Hence, for non-speculative symbolic execution paths, the assumption still holds: if maybe_scc_exit() is called for a state within an SCC, bpf_scc_visit instance must exist.

This patch removes the verifier_bug() call for speculative paths.

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

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).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-40143",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "c9e31900b54cadf5398dfb838c0a63effa1defec",
              "lessThan": "3861e7c4324aa20a632fb74eb3904114f6afdb57",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c9e31900b54cadf5398dfb838c0a63effa1defec",
              "lessThan": "a3c73d629ea1373af3c0c954d41fd1af555492e3",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.17",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.17.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.17.*"
            },
            {
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-11-12T11:15:44.130",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/3861e7c4324aa20a632fb74eb3904114f6afdb57",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a3c73d629ea1373af3c0c954d41fd1af555492e3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: dont report verifier bug for missing bpf_scc_visit on speculative path\n\nSyzbot generated a program that triggers a verifier_bug() call in\nmaybe_exit_scc(). maybe_exit_scc() assumes that, when called for a\nstate with insn_idx in some SCC, there should be an instance of struct\nbpf_scc_visit allocated for that SCC. Turns out the assumption does\nnot hold for speculative execution paths. See example in the next\npatch.\n\nmaybe_scc_exit() is called from update_branch_counts() for states that\nreach branch count of zero, meaning that path exploration for a\nparticular path is finished. Path exploration can finish in one of\nthree ways:\na. Verification error is found. In this case, update_branch_counts()\n   is called only for non-speculative paths.\nb. Top level BPF_EXIT is reached. Such instructions are never a part of\n   an SCC, so compute_scc_callchain() in maybe_scc_exit() will return\n   false, and maybe_scc_exit() will return early.\nc. A checkpoint is reached and matched. Checkpoints are created by\n   is_state_visited(), which calls maybe_enter_scc(), which allocates\n   bpf_scc_visit instances for checkpoints within SCCs.\n\nHence, for non-speculative symbolic execution paths, the assumption\nstill holds: if maybe_scc_exit() is called for a state within an SCC,\nbpf_scc_visit instance must exist.\n\nThis patch removes the verifier_bug() call for speculative paths."
    }
  ],
  "lastModified": "2026-06-17T09:21:20.027",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}