CVE-2026-72426 (GCVE-0-2026-72426)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:44
VLAI
Title
bpf: Preserve pointer spill metadata during half-slot cleanup
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Preserve pointer spill metadata during half-slot cleanup __clean_func_state() cleans dead stack slots in 4-byte halves. When the high half of a STACK_SPILL slot is dead and the low half remains live, cleanup converts the live low half to STACK_MISC or STACK_ZERO and clears the saved spilled_ptr metadata. That conversion is safe only for scalar spills. For a pointer spill, this metadata clear lets a later 32-bit fill from the still-live half avoid the normal non-scalar register-fill check and be treated as an ordinary scalar stack read. Leave non-scalar spill slots intact in this half-live shape. This is conservative for pruning and preserves the existing check_stack_read_fixed_off() rejection path for partial fills from pointer spills.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: be23266b4a08540aa43d8503a2ea10247c8daebe , < 0f9278b22cda6fd2525049930157b79b4036b4ef (git)
Affected: be23266b4a08540aa43d8503a2ea10247c8daebe , < 3a354149bceacadbcf7d7b4766f5ef26a85892ab (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/states.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
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          "product": "Linux",
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          "vendor": "Linux",
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              "status": "unaffected",
              "version": "7.2",
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      "cpeApplicability": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve pointer spill metadata during half-slot cleanup\n\n__clean_func_state() cleans dead stack slots in 4-byte halves. When the\nhigh half of a STACK_SPILL slot is dead and the low half remains live,\ncleanup converts the live low half to STACK_MISC or STACK_ZERO and clears\nthe saved spilled_ptr metadata.\n\nThat conversion is safe only for scalar spills. For a pointer spill, this\nmetadata clear lets a later 32-bit fill from the still-live half avoid the\nnormal non-scalar register-fill check and be treated as an ordinary scalar\nstack read.\n\nLeave non-scalar spill slots intact in this half-live shape. This is\nconservative for pruning and preserves the existing\ncheck_stack_read_fixed_off() rejection path for partial fills from pointer\nspills."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The flaw is reached only through the local bpf(BPF_PROG_LOAD) syscall during BPF verifier state pruning in bpf_is_state_visited()-\u003eclean_verifier_state()-\u003e__clean_func_state(), which is a local kernel interface per BPF CVSS guidance.\nAC:L - An attacker fully controls the crafted BPF bytecode, can spill a pointer, force verifier checkpoints (e.g., BPF_F_TEST_STATE_FREQ or branch pruning), and reliably trigger the half-slot cleanup path without races or external timing.\nPR:N - Exploitation occurs at BPF_PROG_LOAD via bpf(); on systems with kernel.unprivileged_bpf_disabled=0, unprivileged users can load socket-filter programs that trigger this verifier path without CAP_BPF or init-namespace root.\nUI:N - No victim interaction is required; the attacker loads and verifies their own malicious BPF program through the bpf() syscall.\nS:U - Impact is a BPF verifier bypass leading to kernel memory corruption and local privilege escalation within the same kernel security boundary, not a cross-authority escape such as VM guest-to-host.\nC:H - Cleared pointer spill metadata lets partial 32-bit fills bypass non-scalar register-fill checks, causing verifier/runtime type confusion that can be developed into arbitrary kernel memory disclosure primitives.\nI:H - Verifier-approved programs can treat pointer spill bytes as scalars and perform unsafe memory operations, enabling out-of-bounds writes and control-flow hijacking for arbitrary kernel code execution from BPF context.\nA:H - Executing verifier-incorrect BPF with confused pointer/scalar state can trigger kernel oops or panic, and the attacker can repeatedly load and run crafted programs to cause denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:44:06.105Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0f9278b22cda6fd2525049930157b79b4036b4ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/3a354149bceacadbcf7d7b4766f5ef26a85892ab"
        }
      ],
      "title": "bpf: Preserve pointer spill metadata during half-slot cleanup",
      "x_generator": {
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      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72426",
    "datePublished": "2026-08-15T05:56:43.575Z",
    "dateReserved": "2026-08-09T03:40:39.928Z",
    "dateUpdated": "2026-08-17T05:44:06.105Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-72426",
      "date": "2026-09-21",
      "epss": "0.0018",
      "percentile": "0.07768"
    },
    "nvd": {
      "cve": {
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                "product": "Linux",
                "programFiles": [
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                "versions": [
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                    "version": "7.1"
                  },
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                    "version": "0",
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          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve pointer spill metadata during half-slot cleanup\n\n__clean_func_state() cleans dead stack slots in 4-byte halves. When the\nhigh half of a STACK_SPILL slot is dead and the low half remains live,\ncleanup converts the live low half to STACK_MISC or STACK_ZERO and clears\nthe saved spilled_ptr metadata.\n\nThat conversion is safe only for scalar spills. For a pointer spill, this\nmetadata clear lets a later 32-bit fill from the still-live half avoid the\nnormal non-scalar register-fill check and be treated as an ordinary scalar\nstack read.\n\nLeave non-scalar spill slots intact in this half-live shape. This is\nconservative for pruning and preserves the existing\ncheck_stack_read_fixed_off() rejection path for partial fills from pointer\nspills."
          }
        ],
        "id": "CVE-2026-72426",
        "lastModified": "2026-08-17T06:19:09.873",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 8.4,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-08-15T06:22:16.427",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0f9278b22cda6fd2525049930157b79b4036b4ef"
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            "url": "https://git.kernel.org/stable/c/3a354149bceacadbcf7d7b4766f5ef26a85892ab"
          }
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T13:35:47+00:00",
      "cve": "CVE-2026-72426",
      "id": "CVE-2026-72426",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Preserve pointer spill metadata during half-slot cleanup",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72426.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-02T11:45:44Z",
      "cve": "CVE-2026-72426",
      "id": "CVE-2026-72426",
      "initial_release_date": "2026-09-02T11:45:44Z",
      "product_status:known_not_affected": "362",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72426",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72426.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.
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  • 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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.