CVE-2026-52920 (GCVE-0-2026-52920)
Vulnerability from cvelistv5
Published
2026-06-24 07:14
Modified
2026-08-05 12:31
Severity ?
8.3 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_policy: fix strict mode inbound policy matching match_policy_in() walks sec_path entries from the last transform to the first one, but strict policy matching needs to consume info->pol[] in the same forward order as the rule layout. Derive the strict-match policy position from the number of transforms already consumed so that multi-element inbound rules are matched consistently.
References
Impacted products
Vendor Product Version
Linux Linux Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
Version: c4b885139203d37f76662c37ae645fe8e0f4e4e5
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/xt_policy.c"
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          "vendor": "Linux",
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          "vendor": "Linux",
          "versions": [
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              "version": "2.6.17"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "5.10.258",
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              "version": "5.15.209",
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              "status": "unaffected",
              "version": "6.1.175",
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              "status": "unaffected",
              "version": "6.6.141",
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              "status": "unaffected",
              "version": "6.12.91",
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            },
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              "status": "unaffected",
              "version": "6.18.33",
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              "version": "7.0.10",
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              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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\nnetfilter: xt_policy: fix strict mode inbound policy matching\n\nmatch_policy_in() walks sec_path entries from the last transform to the\nfirst one, but strict policy matching needs to consume info-\u003epol[] in\nthe same forward order as the rule layout.\n\nDerive the strict-match policy position from the number of transforms\nalready consumed so that multi-element inbound rules are matched\nconsistently."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.3,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable matcher is executed while processing inbound IPv4/IPv6 packets through x_tables after XFRM/IPsec has populated the packet sec_path. A remote IPsec peer can trigger the affected strict inbound policy rule by sending network packets in a realistic VPN/gateway deployment.\nAC:L - Exploitation requires a strict inbound xt_policy rule with multiple policy elements and a packet with the same number of transforms, but those are normal affected configurations rather than attacker-uncontrolled races. Once present, triggering is repeatable by sending matching packets.\nPR:L - Unauthenticated packets generally fail XFRM state/authentication before reaching this sec_path-based match, so the network scenario requires an authorized IPsec peer or equivalent low privilege. Locally, the rule/XFRM setup is gated by CAP_NET_ADMIN in the network namespace, which is reachable through user namespaces.\nUI:N - No victim user action is needed after the vulnerable rule/state configuration exists. Packet delivery or local namespace traffic is sufficient to invoke the matcher.\nS:U - The bug is in kernel netfilter/XFRM policy evaluation and impacts the same kernel/network security authority. It does not cross a VM, IOMMU, or separate sandbox security scope.\nC:H - The old strict inbound index calculation can make pos negative and read before info-\u003epol[], including x_tables rule metadata or adjacent kernel allocation contents. Although exposed through match behavior rather than a direct copy_to_user, this is an out-of-bounds kernel read larger than a few bytes, so the higher confidentiality impact is warranted.\nI:L - The bug does not provide a direct write primitive or code execution path, but it can make strict IPsec policy matching produce incorrect firewall decisions. That can bypass or misapply intended packet filtering for affected multi-element inbound rules.\nA:H - The negative-index read can reach outside the intended match data and, for larger strict transform counts or unlucky layout, may fault/oops in kernel packet processing. The condition can be triggered repeatedly with packets once the affected rule path is reachable."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:31:42.384Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/eb323f7b82d2e2f638de0cc2a177803eb20e0707"
        },
        {
          "url": "https://git.kernel.org/stable/c/fc1c518bb1f054831ecabb32da9b8e1dff9699c6"
        },
        {
          "url": "https://git.kernel.org/stable/c/f98b7f85e04b40e28b08c461ded0cc79f14f5509"
        },
        {
          "url": "https://git.kernel.org/stable/c/82664d0f1ba25e4f9a71994954abae24c60f4067"
        },
        {
          "url": "https://git.kernel.org/stable/c/b130a6eefa02bd4d475f2f059da8bcfb3e7d18d9"
        },
        {
          "url": "https://git.kernel.org/stable/c/938867e870fb5471bb16f442aeac81326e05bf65"
        },
        {
          "url": "https://git.kernel.org/stable/c/392cc1d8408b5665215c1e9290bbf0f92339b043"
        },
        {
          "url": "https://git.kernel.org/stable/c/4b2b4d7d4e203c92db8966b163edfacb1f0e1e29"
        }
      ],
      "title": "netfilter: xt_policy: fix strict mode inbound policy matching",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-52920",
    "datePublished": "2026-06-24T07:14:15.866Z",
    "dateReserved": "2026-06-09T07:44:35.367Z",
    "dateUpdated": "2026-08-05T12:31:42.384Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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