Vulnerability-Lookup

GHSA-QCMG-5W5P-J7V4

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: Validate iph->ihl in nf_flow_ip4_tunnel_proto()

Add sanity check for iph->ihl field in nf_flow_ip4_tunnel_proto() before using it to compute the header size, avoiding out-of-bounds access with malformed IP headers. While at it, use iph->protocol instead of the hardcoded IPPROTO_IPIP constant when setting ctx->tun.proto and reference ctx->tun.hdr_size when updating ctx->offset.

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-2026-72417"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:15Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: Validate iph-\u003eihl in nf_flow_ip4_tunnel_proto()\n\nAdd sanity check for iph-\u003eihl field in nf_flow_ip4_tunnel_proto() before\nusing it to compute the header size, avoiding out-of-bounds access with\nmalformed IP headers.\nWhile at it, use iph-\u003eprotocol instead of the hardcoded IPPROTO_IPIP\nconstant when setting ctx-\u003etun.proto and reference ctx-\u003etun.hdr_size\nwhen updating ctx-\u003eoffset.",
  "id": "GHSA-qcmg-5w5p-j7v4",
  "modified": "2026-08-17T06:33:28Z",
  "published": "2026-08-15T06:32:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72417"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/025a41e76b51fbc7b8eaa5bacbaa9621d00e6aa7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/84460b644329e25809b4a6d9279d6359d7fd8ebc"
    }
  ],
  "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-2026-72417 (GCVE-0-2026-72417)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:43

Title

netfilter: flowtable: Validate iph->ihl in nf_flow_ip4_tunnel_proto()

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: Validate iph->ihl in nf_flow_ip4_tunnel_proto() Add sanity check for iph->ihl field in nf_flow_ip4_tunnel_proto() before using it to compute the header size, avoiding out-of-bounds access with malformed IP headers. While at it, use iph->protocol instead of the hardcoded IPPROTO_IPIP constant when setting ctx->tun.proto and reference ctx->tun.hdr_size when updating ctx->offset.

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/025a41e76b51fbc7b…
https://git.kernel.org/stable/c/84460b644329e2580…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: ab427db17885814069bae891834f20842f0ac3a4 , < 025a41e76b51fbc7b8eaa5bacbaa9621d00e6aa7 (git) Affected: ab427db17885814069bae891834f20842f0ac3a4 , < 84460b644329e25809b4a6d9279d6359d7fd8ebc (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": "025a41e76b51fbc7b8eaa5bacbaa9621d00e6aa7",
              "status": "affected",
              "version": "ab427db17885814069bae891834f20842f0ac3a4",
              "versionType": "git"
            },
            {
              "lessThan": "84460b644329e25809b4a6d9279d6359d7fd8ebc",
              "status": "affected",
              "version": "ab427db17885814069bae891834f20842f0ac3a4",
              "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",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: Validate iph-\u003eihl in nf_flow_ip4_tunnel_proto()\n\nAdd sanity check for iph-\u003eihl field in nf_flow_ip4_tunnel_proto() before\nusing it to compute the header size, avoiding out-of-bounds access with\nmalformed IP headers.\nWhile at it, use iph-\u003eprotocol instead of the hardcoded IPPROTO_IPIP\nconstant when setting ctx-\u003etun.proto and reference ctx-\u003etun.hdr_size\nwhen updating ctx-\u003eoffset."
        }
      ],
      "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 flaw is hit in nf_flow_offload_ip_hook on NF_NETDEV_INGRESS for IPv4 packets arriving on nftables flowtable devices; a remote attacker can send crafted malformed IP/IPIP headers to that interface without any local access on the victim.\nAC:L - Once a flowtable ingress hook exists, the attacker fully controls packet headers and can reliably reach nf_flow_ip4_tunnel_proto() by sending IP traffic with an invalid ihl field; no race or victim-specific state beyond admin-enabled flow offload is required.\nPR:N - Exploitation requires no credentials or capabilities on the victim host\u2014only that an administrator previously configured nftables flow offload on an ingress device; any remote sender can deliver the malformed packets to trigger parsing on the fast path.\nUI:N - No victim interaction is needed; malicious packets are processed automatically by the netdev ingress netfilter hook during normal receive/forward softirq handling on the configured interface.\nS:U - Impact is kernel memory corruption and crashes within the host kernel security boundary; this is standard in-kernel compromise territory, not a VM escape, IOMMU bypass, or other cross-authority scope change.\nC:H - Missing ihl validation lets iph-\u003eihl\u003c\u003c2 compute an incorrect header size and ctx-\u003eoffset, causing out-of-bounds skb reads in subsequent tuple parsing and forwarding; per kernel guidance, OOB reads warrant High confidentiality impact.\nI:H - Incorrect ctx-\u003eoffset propagates into nf_flow_tuple_ip() and nf_flow_offload_forward(), which invoke skb_ensure_writable() and perform in-place NAT/header mutation at attacker-influenced offsets\u2014memory corruption exploitable for write primitives warrants High integrity impact.\nA:H - Out-of-bounds access in softirq packet processing on the flowtable fast path can trigger KASAN reports, kernel oops, or panics when malformed headers are processed, constituting High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:43:57.257Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/025a41e76b51fbc7b8eaa5bacbaa9621d00e6aa7"
        },
        {
          "url": "https://git.kernel.org/stable/c/84460b644329e25809b4a6d9279d6359d7fd8ebc"
        }
      ],
      "title": "netfilter: flowtable: Validate iph-\u003eihl in nf_flow_ip4_tunnel_proto()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72417",
    "datePublished": "2026-08-15T05:56:37.547Z",
    "dateReserved": "2026-08-09T03:40:39.927Z",
    "dateUpdated": "2026-08-17T05:43:57.257Z",
    "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.

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.

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GHSA-QCMG-5W5P-J7V4

CVE-2026-72417 (GCVE-0-2026-72417)

Tags

Sightings

Nomenclature