CVE-2026-23417 (GCVE-0-2026-23417)

Vulnerability from cvelistv5 – Published: 2026-04-02 11:40 – Updated: 2026-04-13 06:07
VLAI?
Title
bpf: Fix constant blinding for PROBE_MEM32 stores
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix constant blinding for PROBE_MEM32 stores BPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by bpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to survive unblinded into JIT-compiled native code when bpf_jit_harden >= 1. The root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM to BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification, before bpf_jit_blind_constants() runs during JIT compilation. The blinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not BPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through unblinded. Add BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the existing BPF_ST|BPF_MEM cases. The blinding transformation is identical: load the blinded immediate into BPF_REG_AX via mov+xor, then convert the immediate store to a register store (BPF_STX). The rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so the architecture JIT emits the correct arena addressing (R12-based on x86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes BPF_MEM mode; construct the instruction directly instead.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < 56af722756ed82fee2ae5d5b4d04743407506195 (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < ccbf29b28b5554f9d65b2fb53b994673ad58b3bf (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < de641ea08f8fff6906e169d2576c2ac54e562fbb (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < 2321a9596d2260310267622e0ad8fbfa6f95378f (git)
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    Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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              "version": "0",
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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: Fix constant blinding for PROBE_MEM32 stores\n\nBPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by\nbpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to\nsurvive unblinded into JIT-compiled native code when bpf_jit_harden \u003e= 1.\n\nThe root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM\nto BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,\nbefore bpf_jit_blind_constants() runs during JIT compilation. The\nblinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not\nBPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through\nunblinded.\n\nAdd BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the\nexisting BPF_ST|BPF_MEM cases. The blinding transformation is identical:\nload the blinded immediate into BPF_REG_AX via mov+xor, then convert\nthe immediate store to a register store (BPF_STX).\n\nThe rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so\nthe architecture JIT emits the correct arena addressing (R12-based on\nx86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes\nBPF_MEM mode; construct the instruction directly instead."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T06:07:02.830Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/56af722756ed82fee2ae5d5b4d04743407506195"
        },
        {
          "url": "https://git.kernel.org/stable/c/ccbf29b28b5554f9d65b2fb53b994673ad58b3bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/de641ea08f8fff6906e169d2576c2ac54e562fbb"
        },
        {
          "url": "https://git.kernel.org/stable/c/2321a9596d2260310267622e0ad8fbfa6f95378f"
        }
      ],
      "title": "bpf: Fix constant blinding for PROBE_MEM32 stores",
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  },
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23417",
    "datePublished": "2026-04-02T11:40:57.837Z",
    "dateReserved": "2026-01-13T15:37:46.014Z",
    "dateUpdated": "2026-04-13T06:07:02.830Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-23417",
      "date": "2026-04-15",
      "epss": "0.00023",
      "percentile": "0.06212"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23417\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-02T12:16:21.097\",\"lastModified\":\"2026-04-03T16:10:52.680\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbpf: Fix constant blinding for PROBE_MEM32 stores\\n\\nBPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by\\nbpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to\\nsurvive unblinded into JIT-compiled native code when bpf_jit_harden \u003e= 1.\\n\\nThe root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM\\nto BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,\\nbefore bpf_jit_blind_constants() runs during JIT compilation. The\\nblinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not\\nBPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through\\nunblinded.\\n\\nAdd BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the\\nexisting BPF_ST|BPF_MEM cases. The blinding transformation is identical:\\nload the blinded immediate into BPF_REG_AX via mov+xor, then convert\\nthe immediate store to a register store (BPF_STX).\\n\\nThe rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so\\nthe architecture JIT emits the correct arena addressing (R12-based on\\nx86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes\\nBPF_MEM mode; construct the instruction directly instead.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2321a9596d2260310267622e0ad8fbfa6f95378f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/56af722756ed82fee2ae5d5b4d04743407506195\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ccbf29b28b5554f9d65b2fb53b994673ad58b3bf\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/de641ea08f8fff6906e169d2576c2ac54e562fbb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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