Vulnerability-Lookup

CVE-2026-43036 (GCVE-0-2026-43036)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-01 14:15

Title

net: use skb_header_pointer() for TCPv4 GSO frag_off check

Summary

In the Linux kernel, the following vulnerability has been resolved: net: use skb_header_pointer() for TCPv4 GSO frag_off check Syzbot reported a KMSAN uninit-value warning in gso_features_check() called from netif_skb_features() [1]. gso_features_check() reads iph->frag_off to decide whether to clear mangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr() can rely on skb header offsets that are not always safe for direct dereference on packets injected from PF_PACKET paths. Use skb_header_pointer() for the TCPv4 frag_off check so the header read is robust whether data is already linear or needs copying. [1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/f7a6cd508e9e825a2…
	https://git.kernel.org/stable/c/cc91202fc20a44aab…
	https://git.kernel.org/stable/c/d970341cfa5594614…
	https://git.kernel.org/stable/c/ddc748a391dd8642b…

Impacted products

Vendor

Product

Version

Linux

Affected: cbc53e08a793b073e79f42ca33f1f3568703540d , < f7a6cd508e9e825a2c69fa9e13d41ee156852f25 (git)
Affected: cbc53e08a793b073e79f42ca33f1f3568703540d , < cc91202fc20a44aab4c206f12a2bfe05da936051 (git)
Affected: cbc53e08a793b073e79f42ca33f1f3568703540d , < d970341cfa5594614c7a6634886c7688b4f5cafd (git)
Affected: cbc53e08a793b073e79f42ca33f1f3568703540d , < ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0 (git)

Linux

Affected: 4.7
Unaffected: 0 , < 4.7 (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/dev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "f7a6cd508e9e825a2c69fa9e13d41ee156852f25",
              "status": "affected",
              "version": "cbc53e08a793b073e79f42ca33f1f3568703540d",
              "versionType": "git"
            },
            {
              "lessThan": "cc91202fc20a44aab4c206f12a2bfe05da936051",
              "status": "affected",
              "version": "cbc53e08a793b073e79f42ca33f1f3568703540d",
              "versionType": "git"
            },
            {
              "lessThan": "d970341cfa5594614c7a6634886c7688b4f5cafd",
              "status": "affected",
              "version": "cbc53e08a793b073e79f42ca33f1f3568703540d",
              "versionType": "git"
            },
            {
              "lessThan": "ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0",
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              "version": "cbc53e08a793b073e79f42ca33f1f3568703540d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/dev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.7"
            },
            {
              "lessThan": "4.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.81",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.81",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.22",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.12",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: use skb_header_pointer() for TCPv4 GSO frag_off check\n\nSyzbot reported a KMSAN uninit-value warning in gso_features_check()\ncalled from netif_skb_features() [1].\n\ngso_features_check() reads iph-\u003efrag_off to decide whether to clear\nmangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr()\ncan rely on skb header offsets that are not always safe for direct\ndereference on packets injected from PF_PACKET paths.\n\nUse skb_header_pointer() for the TCPv4 frag_off check so the header read\nis robust whether data is already linear or needs copying.\n\n[1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-01T14:15:34.640Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25"
        },
        {
          "url": "https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051"
        },
        {
          "url": "https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd"
        },
        {
          "url": "https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0"
        }
      ],
      "title": "net: use skb_header_pointer() for TCPv4 GSO frag_off check",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43036",
    "datePublished": "2026-05-01T14:15:34.640Z",
    "dateReserved": "2026-05-01T14:12:55.977Z",
    "dateUpdated": "2026-05-01T14:15:34.640Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-43036",
      "date": "2026-05-04",
      "epss": "0.00018",
      "percentile": "0.04648"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43036\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-01T15:16:48.273\",\"lastModified\":\"2026-05-01T15:24:14.893\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: use skb_header_pointer() for TCPv4 GSO frag_off check\\n\\nSyzbot reported a KMSAN uninit-value warning in gso_features_check()\\ncalled from netif_skb_features() [1].\\n\\ngso_features_check() reads iph-\u003efrag_off to decide whether to clear\\nmangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr()\\ncan rely on skb header offsets that are not always safe for direct\\ndereference on packets injected from PF_PACKET paths.\\n\\nUse skb_header_pointer() for the TCPv4 frag_off check so the header read\\nis robust whether data is already linear or needs copying.\\n\\n[1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

MSRC_CVE-2026-43036

Vulnerability from csaf_microsoft - Published: 2026-05-02 00:00 - Updated: 2026-05-02 01:02

Summary

net: use skb_header_pointer() for TCPv4 GSO frag_off check

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-43036

References

URL

Category

	https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
	https://support.microsoft.com/lifecycle	external
	https://www.first.org/cvss	external
	https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-43036 net: use skb_header_pointer() for TCPv4 GSO frag_off check - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-43036.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "net: use skb_header_pointer() for TCPv4 GSO frag_off check",
    "tracking": {
      "current_release_date": "2026-05-02T01:02:14.000Z",
      "generator": {
        "date": "2026-05-03T07:02:17.470Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-43036",
      "initial_release_date": "2026-05-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-05-02T01:02:14.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-43036",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "under_investigation": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-43036 net: use skb_header_pointer() for TCPv4 GSO frag_off check - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-43036.json"
        }
      ],
      "title": "net: use skb_header_pointer() for TCPv4 GSO frag_off check"
    }
  ]
}

FKIE_CVE-2026-43036

Vulnerability from fkie_nvd - Published: 2026-05-01 15:16 - Updated: 2026-05-01 15:24

Severity ?

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: use skb_header_pointer() for TCPv4 GSO frag_off check\n\nSyzbot reported a KMSAN uninit-value warning in gso_features_check()\ncalled from netif_skb_features() [1].\n\ngso_features_check() reads iph-\u003efrag_off to decide whether to clear\nmangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr()\ncan rely on skb header offsets that are not always safe for direct\ndereference on packets injected from PF_PACKET paths.\n\nUse skb_header_pointer() for the TCPv4 frag_off check so the header read\nis robust whether data is already linear or needs copying.\n\n[1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407"
    }
  ],
  "id": "CVE-2026-43036",
  "lastModified": "2026-05-01T15:24:14.893",
  "metrics": {},
  "published": "2026-05-01T15:16:48.273",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

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.

Action not permitted

CVE-2026-43036 (GCVE-0-2026-43036)

MSRC_CVE-2026-43036

FKIE_CVE-2026-43036

Tags

Sightings

Nomenclature