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GHSA-3XPJ-Q99R-5475

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

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

netfilter: flowtable: use dst in this direction when pushing IPIP header

When pushing the IPIP header, the route of the other direction is used to calculate the headroom, use the route in this direction. Accessing the other tuple to set the IP source and destination is fine because this tuple does not provide such information to avoid storing redundant information. However, this tuple already provides the dst for this direction, this went unnoticed because this bug affects headroom and iph->frag_off only at this stage.

Severity

9.8 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72249"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:52Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: use dst in this direction when pushing IPIP header\n\nWhen pushing the IPIP header, the route of the other direction is used\nto calculate the headroom, use the route in this direction. Accessing\nthe other tuple to set the IP source and destination is fine because\nthis tuple does not provide such information to avoid storing redundant\ninformation. However, this tuple already provides the dst for this\ndirection, this went unnoticed because this bug affects headroom and\niph-\u003efrag_off only at this stage.",
  "id": "GHSA-3xpj-q99r-5475",
  "modified": "2026-08-17T06:33:18Z",
  "published": "2026-08-15T06:32:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72249"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c328b90c17fc5fa7786503695152880b2afb9326"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ecb78fbb03d3f86e2e93767875e273308086a424"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-72249 (GCVE-0-2026-72249)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-17 05:42

Title

netfilter: flowtable: use dst in this direction when pushing IPIP header

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: use dst in this direction when pushing IPIP header When pushing the IPIP header, the route of the other direction is used to calculate the headroom, use the route in this direction. Accessing the other tuple to set the IP source and destination is fine because this tuple does not provide such information to avoid storing redundant information. However, this tuple already provides the dst for this direction, this went unnoticed because this bug affects headroom and iph->frag_off only at this stage.

Severity

9.8 (Critical)


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

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/ecb78fbb03d3f86e2…
https://git.kernel.org/stable/c/c328b90c17fc5fa77…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: d30301ba4b07ac92eb38353a111833b009003170 , < ecb78fbb03d3f86e2e93767875e273308086a424 (git) Affected: d30301ba4b07ac92eb38353a111833b009003170 , < c328b90c17fc5fa7786503695152880b2afb9326 (git)
Linux	Linux	Affected: 6.19 Unaffected: 0 , < 6.19 (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_flow_table_ip.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ecb78fbb03d3f86e2e93767875e273308086a424",
              "status": "affected",
              "version": "d30301ba4b07ac92eb38353a111833b009003170",
              "versionType": "git"
            },
            {
              "lessThan": "c328b90c17fc5fa7786503695152880b2afb9326",
              "status": "affected",
              "version": "d30301ba4b07ac92eb38353a111833b009003170",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_flow_table_ip.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
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                }
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: use dst in this direction when pushing IPIP header\n\nWhen pushing the IPIP header, the route of the other direction is used\nto calculate the headroom, use the route in this direction. Accessing\nthe other tuple to set the IP source and destination is fine because\nthis tuple does not provide such information to avoid storing redundant\ninformation. However, this tuple already provides the dst for this\ndirection, this went unnoticed because this bug affects headroom and\niph-\u003efrag_off only at this stage."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is hit in the netfilter flowtable ingress fast path when offloaded TCP/UDP packets are received on bound netdevs and tunnel encapsulation runs; a remote peer can trigger it by sending traffic through an IPIP flow-offload gateway without local access.\nAC:L - After a flow is offloaded (easily created by the attacker\u0027s own connections), asymmetric IPIP gateway routing predictably makes the reverse-direction dst underestimate headroom, so skb_cow_head undersizes and skb_push corrupts memory on each matching packet.\nPR:N - The attacker only needs to send network packets that match an established offloaded flow; nftables flowtable/IPIP setup is an administrator deployment precondition, not a privilege the attacker must hold on the target system.\nUI:N - No victim user action is required beyond normal network traffic once flow offload is enabled; exploitation is driven entirely by packets the attacker sends to the gateway.\nS:U - Impact is confined to kernel heap memory corruption and potential local privilege escalation within the same host; it does not cross VM, container, or IOMMU security boundaries.\nC:H - Undersized headroom lets skb_push write before skb-\u003ehead, causing out-of-bounds heap corruption that can expose adjacent kernel objects and be leveraged into arbitrary memory disclosure primitives.\nI:H - The same skb head underflow is a writable heap corruption primitive that can overwrite adjacent allocator metadata or object contents and be developed into arbitrary kernel code execution.\nA:H - Heap corruption from skb_push underflow can immediately kernel oops/panic the system or be triggered repeatedly to deny service on an internet-facing VPN/edge gateway."
            }
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        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:42:01.084Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72249",
    "datePublished": "2026-08-15T05:54:37.914Z",
    "dateReserved": "2026-08-09T03:40:39.914Z",
    "dateUpdated": "2026-08-17T05:42:01.084Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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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.
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GHSA-3XPJ-Q99R-5475

CVE-2026-72249 (GCVE-0-2026-72249)

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