Vulnerability-Lookup

GHSA-3J46-WX9H-X693

Vulnerability from github – Published: 2026-04-02 12:31 – Updated: 2026-04-24 15:32

Details

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 ?

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23417"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-02T12:16:21Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-3j46-wx9h-x693",
  "modified": "2026-04-24T15:32:20Z",
  "published": "2026-04-02T12:31:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23417"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2321a9596d2260310267622e0ad8fbfa6f95378f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/56af722756ed82fee2ae5d5b4d04743407506195"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ccbf29b28b5554f9d65b2fb53b994673ad58b3bf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de641ea08f8fff6906e169d2576c2ac54e562fbb"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-04-02 11:40 – Updated: 2026-04-13 06:07

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

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/56af722756ed82fee…
	https://git.kernel.org/stable/c/ccbf29b28b5554f9d…
	https://git.kernel.org/stable/c/de641ea08f8fff690…
	https://git.kernel.org/stable/c/2321a9596d2260310…

Impacted products

Vendor

Product

Version

Linux

Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < 56af722756ed82fee2ae5d5b4d04743407506195 (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < ccbf29b28b5554f9d65b2fb53b994673ad58b3bf (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < de641ea08f8fff6906e169d2576c2ac54e562fbb (git)
Affected: 6082b6c328b5486da2b356eae94b8b83c98b5565 , < 2321a9596d2260310267622e0ad8fbfa6f95378f (git)

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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "56af722756ed82fee2ae5d5b4d04743407506195",
              "status": "affected",
              "version": "6082b6c328b5486da2b356eae94b8b83c98b5565",
              "versionType": "git"
            },
            {
              "lessThan": "ccbf29b28b5554f9d65b2fb53b994673ad58b3bf",
              "status": "affected",
              "version": "6082b6c328b5486da2b356eae94b8b83c98b5565",
              "versionType": "git"
            },
            {
              "lessThan": "de641ea08f8fff6906e169d2576c2ac54e562fbb",
              "status": "affected",
              "version": "6082b6c328b5486da2b356eae94b8b83c98b5565",
              "versionType": "git"
            },
            {
              "lessThan": "2321a9596d2260310267622e0ad8fbfa6f95378f",
              "status": "affected",
              "version": "6082b6c328b5486da2b356eae94b8b83c98b5565",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.80",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.80",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.21",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.11",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "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"
}

Sightings

Author	Source	Type	Date	Other

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-3J46-WX9H-X693

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

Tags

Sightings

Nomenclature