Vulnerability-Lookup

GHSA-QGCC-GWGQ-PQ62

Vulnerability from github – Published: 2026-06-24 09:30 – Updated: 2026-06-28 09:31

Details

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.

Severity

8.3 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-52920"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T08:16:21Z",
    "severity": "HIGH"
  },
  "details": "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.",
  "id": "GHSA-qgcc-gwgq-pq62",
  "modified": "2026-06-28T09:31:36Z",
  "published": "2026-06-24T09:30:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52920"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/392cc1d8408b5665215c1e9290bbf0f92339b043"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b2b4d7d4e203c92db8966b163edfacb1f0e1e29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/82664d0f1ba25e4f9a71994954abae24c60f4067"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/938867e870fb5471bb16f442aeac81326e05bf65"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b130a6eefa02bd4d475f2f059da8bcfb3e7d18d9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb323f7b82d2e2f638de0cc2a177803eb20e0707"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f98b7f85e04b40e28b08c461ded0cc79f14f5509"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc1c518bb1f054831ecabb32da9b8e1dff9699c6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-52920 (GCVE-0-2026-52920)

Vulnerability from cvelistv5 – Published: 2026-06-24 07:14 – Updated: 2026-08-05 12:31

Title

netfilter: xt_policy: fix strict mode inbound policy matching

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.

Severity

8.3 (High)


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

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/eb323f7b82d2e2f63…
https://git.kernel.org/stable/c/fc1c518bb1f054831…
https://git.kernel.org/stable/c/f98b7f85e04b40e28…
https://git.kernel.org/stable/c/82664d0f1ba25e4f9…
https://git.kernel.org/stable/c/b130a6eefa02bd4d4…
https://git.kernel.org/stable/c/938867e870fb5471b…
https://git.kernel.org/stable/c/392cc1d8408b56652…
https://git.kernel.org/stable/c/4b2b4d7d4e203c92d…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < eb323f7b82d2e2f638de0cc2a177803eb20e0707 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < fc1c518bb1f054831ecabb32da9b8e1dff9699c6 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < f98b7f85e04b40e28b08c461ded0cc79f14f5509 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < 82664d0f1ba25e4f9a71994954abae24c60f4067 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < b130a6eefa02bd4d475f2f059da8bcfb3e7d18d9 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < 938867e870fb5471bb16f442aeac81326e05bf65 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < 392cc1d8408b5665215c1e9290bbf0f92339b043 (git) Affected: c4b885139203d37f76662c37ae645fe8e0f4e4e5 , < 4b2b4d7d4e203c92db8966b163edfacb1f0e1e29 (git)
Linux	Linux	Affected: 2.6.17 Unaffected: 0 , < 2.6.17 (semver) Unaffected: 5.10.258 , ≤ 5.10.* (semver) Unaffected: 5.15.209 , ≤ 5.15.* (semver) Unaffected: 6.1.175 , ≤ 6.1.* (semver) Unaffected: 6.6.141 , ≤ 6.6.* (semver) Unaffected: 6.12.91 , ≤ 6.12.* (semver) Unaffected: 6.18.33 , ≤ 6.18.* (semver) Unaffected: 7.0.10 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/xt_policy.c"
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          "vendor": "Linux",
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              "version": "0",
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              "status": "unaffected",
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              "versionType": "semver"
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              "version": "6.18.33",
              "versionType": "semver"
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          "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."
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            "baseSeverity": "HIGH",
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            "version": "3.1"
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              "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."
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        "dateUpdated": "2026-08-05T12:31:42.384Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        {
          "url": "https://git.kernel.org/stable/c/4b2b4d7d4e203c92db8966b163edfacb1f0e1e29"
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      "title": "netfilter: xt_policy: fix strict mode inbound policy matching",
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    "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"
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}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.