Vulnerability-Lookup

CVE-2026-31413 (GCVE-0-2026-31413)

Vulnerability from cvelistv5 – Published: 2026-04-12 05:36 – Updated: 2026-04-12 05:36

Title

bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR maybe_fork_scalars() is called for both BPF_AND and BPF_OR when the source operand is a constant. When dst has signed range [-1, 0], it forks the verifier state: the pushed path gets dst = 0, the current path gets dst = -1. For BPF_AND this is correct: 0 & K == 0. For BPF_OR this is wrong: 0 | K == K, not 0. The pushed path therefore tracks dst as 0 when the runtime value is K, producing an exploitable verifier/runtime divergence that allows out-of-bounds map access. Fix this by passing env->insn_idx (instead of env->insn_idx + 1) to push_stack(), so the pushed path re-executes the ALU instruction with dst = 0 and naturally computes the correct result for any opcode.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/342aa1ee995ef5bbf…
	https://git.kernel.org/stable/c/58bd87d0e69204dbd…
	https://git.kernel.org/stable/c/d13281ae7ea8902b2…
	https://git.kernel.org/stable/c/c845894ebd6fb4322…

Impacted products

Vendor

Product

Version

Linux

Affected: dea9989a3f3961faede93752cd81eb5a9514d911 , < 342aa1ee995ef5bbf876096dc3a5e51218d76fa4 (git)
Affected: 4c122e8ae14950cf6b59d208fc5160f7c601e746 , < 58bd87d0e69204dbd739e4387a1edb0c4b1644e7 (git)
Affected: e52567173ba86dbffb990595fbe60e2e83899372 , < d13281ae7ea8902b21d99d10a2c8caf0bdec0455 (git)
Affected: bffacdb80b93b7b5e96b26fad64cc490a6c7d6c7 , < c845894ebd6fb43226b3118d6b017942550910c5 (git)

Linux

Affected: 7.0-rc1
Unaffected: 0 , < 7.0-rc1 (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-rc5 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
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              "versionType": "git"
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              "version": "4c122e8ae14950cf6b59d208fc5160f7c601e746",
              "versionType": "git"
            },
            {
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              "version": "e52567173ba86dbffb990595fbe60e2e83899372",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "bffacdb80b93b7b5e96b26fad64cc490a6c7d6c7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0-rc1"
            },
            {
              "lessThan": "7.0-rc1",
              "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-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.80",
                  "versionStartIncluding": "6.12.75",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.21",
                  "versionStartIncluding": "6.18.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.11",
                  "versionStartIncluding": "6.19.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0-rc5",
                  "versionStartIncluding": "7.0-rc1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR\n\nmaybe_fork_scalars() is called for both BPF_AND and BPF_OR when the\nsource operand is a constant.  When dst has signed range [-1, 0], it\nforks the verifier state: the pushed path gets dst = 0, the current\npath gets dst = -1.\n\nFor BPF_AND this is correct: 0 \u0026 K == 0.\nFor BPF_OR this is wrong:    0 | K == K, not 0.\n\nThe pushed path therefore tracks dst as 0 when the runtime value is K,\nproducing an exploitable verifier/runtime divergence that allows\nout-of-bounds map access.\n\nFix this by passing env-\u003einsn_idx (instead of env-\u003einsn_idx + 1) to\npush_stack(), so the pushed path re-executes the ALU instruction with\ndst = 0 and naturally computes the correct result for any opcode."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-12T05:36:14.632Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/342aa1ee995ef5bbf876096dc3a5e51218d76fa4"
        },
        {
          "url": "https://git.kernel.org/stable/c/58bd87d0e69204dbd739e4387a1edb0c4b1644e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/d13281ae7ea8902b21d99d10a2c8caf0bdec0455"
        },
        {
          "url": "https://git.kernel.org/stable/c/c845894ebd6fb43226b3118d6b017942550910c5"
        }
      ],
      "title": "bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR",
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      }
    }
  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31413",
    "datePublished": "2026-04-12T05:36:14.632Z",
    "dateReserved": "2026-03-09T15:48:24.087Z",
    "dateUpdated": "2026-04-12T05:36:14.632Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31413\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-12T06:16:20.050\",\"lastModified\":\"2026-04-12T06:16:20.050\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR\\n\\nmaybe_fork_scalars() is called for both BPF_AND and BPF_OR when the\\nsource operand is a constant.  When dst has signed range [-1, 0], it\\nforks the verifier state: the pushed path gets dst = 0, the current\\npath gets dst = -1.\\n\\nFor BPF_AND this is correct: 0 \u0026 K == 0.\\nFor BPF_OR this is wrong:    0 | K == K, not 0.\\n\\nThe pushed path therefore tracks dst as 0 when the runtime value is K,\\nproducing an exploitable verifier/runtime divergence that allows\\nout-of-bounds map access.\\n\\nFix this by passing env-\u003einsn_idx (instead of env-\u003einsn_idx + 1) to\\npush_stack(), so the pushed path re-executes the ALU instruction with\\ndst = 0 and naturally computes the correct result for any opcode.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/342aa1ee995ef5bbf876096dc3a5e51218d76fa4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/58bd87d0e69204dbd739e4387a1edb0c4b1644e7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c845894ebd6fb43226b3118d6b017942550910c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d13281ae7ea8902b21d99d10a2c8caf0bdec0455\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

GHSA-Q7PG-XJGF-WR6F

Vulnerability from github – Published: 2026-04-12 06:30 – Updated: 2026-04-12 06:30

Details

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

bpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR

maybe_fork_scalars() is called for both BPF_AND and BPF_OR when the source operand is a constant. When dst has signed range [-1, 0], it forks the verifier state: the pushed path gets dst = 0, the current path gets dst = -1.

For BPF_AND this is correct: 0 & K == 0. For BPF_OR this is wrong: 0 | K == K, not 0.

The pushed path therefore tracks dst as 0 when the runtime value is K, producing an exploitable verifier/runtime divergence that allows out-of-bounds map access.

Fix this by passing env->insn_idx (instead of env->insn_idx + 1) to push_stack(), so the pushed path re-executes the ALU instruction with dst = 0 and naturally computes the correct result for any opcode.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-31413"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-12T06:16:20Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix unsound scalar forking in maybe_fork_scalars() for BPF_OR\n\nmaybe_fork_scalars() is called for both BPF_AND and BPF_OR when the\nsource operand is a constant.  When dst has signed range [-1, 0], it\nforks the verifier state: the pushed path gets dst = 0, the current\npath gets dst = -1.\n\nFor BPF_AND this is correct: 0 \u0026 K == 0.\nFor BPF_OR this is wrong:    0 | K == K, not 0.\n\nThe pushed path therefore tracks dst as 0 when the runtime value is K,\nproducing an exploitable verifier/runtime divergence that allows\nout-of-bounds map access.\n\nFix this by passing env-\u003einsn_idx (instead of env-\u003einsn_idx + 1) to\npush_stack(), so the pushed path re-executes the ALU instruction with\ndst = 0 and naturally computes the correct result for any opcode.",
  "id": "GHSA-q7pg-xjgf-wr6f",
  "modified": "2026-04-12T06:30:27Z",
  "published": "2026-04-12T06:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31413"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/342aa1ee995ef5bbf876096dc3a5e51218d76fa4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/58bd87d0e69204dbd739e4387a1edb0c4b1644e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c845894ebd6fb43226b3118d6b017942550910c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d13281ae7ea8902b21d99d10a2c8caf0bdec0455"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date

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

CVE-2026-31413 (GCVE-0-2026-31413)

GHSA-Q7PG-XJGF-WR6F

Tags

Sightings

Nomenclature