FKIE_CVE-2026-53036

Vulnerability from fkie_nvd - Published: 2026-06-24 17:17 - Updated: 2026-06-28 08:16
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, arm64: Fix off-by-one in check_imm signed range check check_imm(bits, imm) is used in the arm64 BPF JIT to verify that a branch displacement (in arm64 instruction units) fits into the signed N-bit immediate field of a B, B.cond or CBZ/CBNZ encoding before it is handed to the encoder. The macro currently tests for (imm > 0 && imm >> bits) || (imm < 0 && ~imm >> bits) which admits values in [-2^N, 2^N) — effectively a signed (N+1)-bit range. A signed N-bit field only holds [-2^(N-1), 2^(N-1)), so the check admits one extra bit of range on each side. In particular, for check_imm19(), values in [2^18, 2^19) slip past the check but do not fit into the 19-bit signed imm19 field of B.cond. aarch64_insn_encode_immediate() then masks the raw value into the 19-bit field, setting bit 18 (the sign bit) and flipping a forward branch into a backward one. Same class of issue exists for check_imm26() and the B/BL encoding. Shift by (bits - 1) instead of bits so the actual signed N-bit range is enforced.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1a113b5497297871699cd498b1b83542e0db7f15
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1dd8be4ec722ce54e4cace59f3a4ba658111b3ec
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6927f0d6794aa73318bbfa929f1ff6065b0620df
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7fd3b41260c6120e7b60164afea5d961af6224f9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a5dfeb3b61065039488342d43ae06d4729d955d4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fb74defa1cca1a73177c0c761e641332e4f979a3
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/net/bpf_jit_comp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a5dfeb3b61065039488342d43ae06d4729d955d4",
              "status": "affected",
              "version": "e54bcde3d69d40023ae77727213d14f920eb264a",
              "versionType": "git"
            },
            {
              "lessThan": "7fd3b41260c6120e7b60164afea5d961af6224f9",
              "status": "affected",
              "version": "e54bcde3d69d40023ae77727213d14f920eb264a",
              "versionType": "git"
            },
            {
              "lessThan": "6927f0d6794aa73318bbfa929f1ff6065b0620df",
              "status": "affected",
              "version": "e54bcde3d69d40023ae77727213d14f920eb264a",
              "versionType": "git"
            },
            {
              "lessThan": "1a113b5497297871699cd498b1b83542e0db7f15",
              "status": "affected",
              "version": "e54bcde3d69d40023ae77727213d14f920eb264a",
              "versionType": "git"
            },
            {
              "lessThan": "fb74defa1cca1a73177c0c761e641332e4f979a3",
              "status": "affected",
              "version": "e54bcde3d69d40023ae77727213d14f920eb264a",
              "versionType": "git"
            },
            {
              "lessThan": "1dd8be4ec722ce54e4cace59f3a4ba658111b3ec",
              "status": "affected",
              "version": "e54bcde3d69d40023ae77727213d14f920eb264a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/net/bpf_jit_comp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.18"
            },
            {
              "lessThan": "3.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.141",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.91",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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, arm64: Fix off-by-one in check_imm signed range check\n\ncheck_imm(bits, imm) is used in the arm64 BPF JIT to verify that\na branch displacement (in arm64 instruction units) fits into the\nsigned N-bit immediate field of a B, B.cond or CBZ/CBNZ encoding\nbefore it is handed to the encoder. The macro currently tests for\n(imm \u003e 0 \u0026\u0026 imm \u003e\u003e bits) || (imm \u003c 0 \u0026\u0026 ~imm \u003e\u003e bits) which admits\nvalues in [-2^N, 2^N) \u2014 effectively a signed (N+1)-bit range. A\nsigned N-bit field only holds [-2^(N-1), 2^(N-1)), so the check\nadmits one extra bit of range on each side.\n\nIn particular, for check_imm19(), values in [2^18, 2^19) slip past\nthe check but do not fit into the 19-bit signed imm19 field of\nB.cond. aarch64_insn_encode_immediate() then masks the raw value\ninto the 19-bit field, setting bit 18 (the sign bit) and flipping\na forward branch into a backward one. Same class of issue exists\nfor check_imm26() and the B/BL encoding. Shift by (bits - 1)\ninstead of bits so the actual signed N-bit range is enforced."
    }
  ],
  "id": "CVE-2026-53036",
  "lastModified": "2026-06-28T08:16:30.453",
  "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"
      }
    ]
  },
  "published": "2026-06-24T17:17:15.137",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1a113b5497297871699cd498b1b83542e0db7f15"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1dd8be4ec722ce54e4cace59f3a4ba658111b3ec"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6927f0d6794aa73318bbfa929f1ff6065b0620df"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7fd3b41260c6120e7b60164afea5d961af6224f9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a5dfeb3b61065039488342d43ae06d4729d955d4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fb74defa1cca1a73177c0c761e641332e4f979a3"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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