Vulnerability-Lookup

GHSA-6727-4WMG-W3RC

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

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

net/openvswitch: check Ethernet header length in key_extract()

When a packet arrives on an ARPHRD_NONE device (e.g. TUN), ovs_flow_key_extract() trusts the user-provided skb->protocol field: if it is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and key_extract() is called without ensuring the skb has ETH_HLEN (14) bytes of linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes for MAC addresses and parse_ethertype() pulls 2 more, either of which triggers a kernel BUG in __skb_pull() when the linear area is too small.

kernel BUG at include/linux/skbuff.h:2848! RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933 ovs_flow_key_extract+0x419/0xa70 ovs_vport_receive+0x222/0x390 netdev_frame_hook+0x3e0/0x630 tun_get_user+0x2d0c/0x38e0

Fixed by calling check_header() in key_extract() before accessing the Ethernet header.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74701"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:44Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/openvswitch: check Ethernet header length in key_extract()\n\nWhen a packet arrives on an ARPHRD_NONE device (e.g. TUN),\novs_flow_key_extract() trusts the user-provided skb-\u003eprotocol field: if\nit is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and\nkey_extract() is called without ensuring the skb has ETH_HLEN (14) bytes\nof linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes\nfor MAC addresses and parse_ethertype() pulls 2 more, either of which\ntriggers a kernel BUG in __skb_pull() when the linear area is too small.\n\n  kernel BUG at include/linux/skbuff.h:2848!\n  RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933\n  ovs_flow_key_extract+0x419/0xa70\n  ovs_vport_receive+0x222/0x390\n  netdev_frame_hook+0x3e0/0x630\n  tun_get_user+0x2d0c/0x38e0\n\nFixed by calling check_header() in key_extract() before accessing the\nEthernet header.",
  "id": "GHSA-6727-4wmg-w3rc",
  "modified": "2026-08-25T06:31:28Z",
  "published": "2026-08-22T18:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74701"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0b60b55652ba772b173dddc63f3851e1d2dd5927"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81f9b09f0ea3ba9ab966dd17e9f32625a14555e9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/831471718f6e19aed1a330b03b53190a90e06466"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9b8cfbb58b85bfa7a78fac47fdc77396cd01f699"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a8139285c8925efe59af28a9169bb2fda91bff15"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf6f8b29befb92173659bcef6a441d274947bfae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d8bea341b183190ce6c055ab0e64ab78eb9a7290"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e85278afd4890dd190ba3c7a1b1a712b801c9fe1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-74701 (GCVE-0-2026-74701)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-25 05:41

Title

net/openvswitch: check Ethernet header length in key_extract()

Summary

In the Linux kernel, the following vulnerability has been resolved: net/openvswitch: check Ethernet header length in key_extract() When a packet arrives on an ARPHRD_NONE device (e.g. TUN), ovs_flow_key_extract() trusts the user-provided skb->protocol field: if it is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and key_extract() is called without ensuring the skb has ETH_HLEN (14) bytes of linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes for MAC addresses and parse_ethertype() pulls 2 more, either of which triggers a kernel BUG in __skb_pull() when the linear area is too small. kernel BUG at include/linux/skbuff.h:2848! RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933 ovs_flow_key_extract+0x419/0xa70 ovs_vport_receive+0x222/0x390 netdev_frame_hook+0x3e0/0x630 tun_get_user+0x2d0c/0x38e0 Fixed by calling check_header() in key_extract() before accessing the Ethernet header.

Severity

7.8 (High)


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

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/e85278afd4890dd19…
https://git.kernel.org/stable/c/81f9b09f0ea3ba9ab…
https://git.kernel.org/stable/c/831471718f6e19aed…
https://git.kernel.org/stable/c/d8bea341b183190ce…
https://git.kernel.org/stable/c/0b60b55652ba772b1…
https://git.kernel.org/stable/c/a8139285c8925efe5…
https://git.kernel.org/stable/c/9b8cfbb58b85bfa7a…
https://git.kernel.org/stable/c/cf6f8b29befb92173…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < e85278afd4890dd190ba3c7a1b1a712b801c9fe1 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < 81f9b09f0ea3ba9ab966dd17e9f32625a14555e9 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < 831471718f6e19aed1a330b03b53190a90e06466 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < d8bea341b183190ce6c055ab0e64ab78eb9a7290 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < 0b60b55652ba772b173dddc63f3851e1d2dd5927 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < a8139285c8925efe59af28a9169bb2fda91bff15 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < 9b8cfbb58b85bfa7a78fac47fdc77396cd01f699 (git) Affected: 217ac77a3c2524d999730b2a80b61fcc2d0f734a , < cf6f8b29befb92173659bcef6a441d274947bfae (git)
Linux	Linux	Affected: 4.10 Unaffected: 0 , < 4.10 (semver) Unaffected: 5.10.265 , ≤ 5.10.* (semver) Unaffected: 5.15.216 , ≤ 5.15.* (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.152 , ≤ 6.6.* (semver) Unaffected: 6.12.104 , ≤ 6.12.* (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/openvswitch/flow.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e85278afd4890dd190ba3c7a1b1a712b801c9fe1",
              "status": "affected",
              "version": "217ac77a3c2524d999730b2a80b61fcc2d0f734a",
              "versionType": "git"
            },
            {
              "lessThan": "81f9b09f0ea3ba9ab966dd17e9f32625a14555e9",
              "status": "affected",
              "version": "217ac77a3c2524d999730b2a80b61fcc2d0f734a",
              "versionType": "git"
            },
            {
              "lessThan": "831471718f6e19aed1a330b03b53190a90e06466",
              "status": "affected",
              "version": "217ac77a3c2524d999730b2a80b61fcc2d0f734a",
              "versionType": "git"
            },
            {
              "lessThan": "d8bea341b183190ce6c055ab0e64ab78eb9a7290",
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              "versionType": "git"
            },
            {
              "lessThan": "0b60b55652ba772b173dddc63f3851e1d2dd5927",
              "status": "affected",
              "version": "217ac77a3c2524d999730b2a80b61fcc2d0f734a",
              "versionType": "git"
            },
            {
              "lessThan": "a8139285c8925efe59af28a9169bb2fda91bff15",
              "status": "affected",
              "version": "217ac77a3c2524d999730b2a80b61fcc2d0f734a",
              "versionType": "git"
            },
            {
              "lessThan": "9b8cfbb58b85bfa7a78fac47fdc77396cd01f699",
              "status": "affected",
              "version": "217ac77a3c2524d999730b2a80b61fcc2d0f734a",
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          "programFiles": [
            "net/openvswitch/flow.c"
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.10"
            },
            {
              "lessThan": "4.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
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                  "versionEndExcluding": "5.10.265",
                  "versionStartIncluding": "4.10",
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                },
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                },
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                  "vulnerable": true
                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "4.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "4.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "4.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/openvswitch: check Ethernet header length in key_extract()\n\nWhen a packet arrives on an ARPHRD_NONE device (e.g. TUN),\novs_flow_key_extract() trusts the user-provided skb-\u003eprotocol field: if\nit is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and\nkey_extract() is called without ensuring the skb has ETH_HLEN (14) bytes\nof linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes\nfor MAC addresses and parse_ethertype() pulls 2 more, either of which\ntriggers a kernel BUG in __skb_pull() when the linear area is too small.\n\n  kernel BUG at include/linux/skbuff.h:2848!\n  RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933\n  ovs_flow_key_extract+0x419/0xa70\n  ovs_vport_receive+0x222/0x390\n  netdev_frame_hook+0x3e0/0x630\n  tun_get_user+0x2d0c/0x38e0\n\nFixed by calling check_header() in key_extract() before accessing the\nEthernet header."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The crash is reached when a crafted skb is processed in ovs_flow_key_extract() via ovs_vport_receive(); the documented reproducer injects it through tun_get_user() (write to a TUN fd), and the alternate path is OVS_PACKET_CMD_EXECUTE netlink\u2014both require local syscall access, not remote packet delivery.\nAC:L - The attacker fully controls skb length, skb-\u003eprotocol (ETH_P_TEB), and linear versus fragmented layout; sending a sub-14-byte payload with ETH_P_TEB on an ARPHRD_NONE OVS port deterministically reaches key_extract() and triggers __skb_pull() BUG() without races or special heap layout.\nPR:L - Attaching an ARPHRD_NONE netdev to an OVS datapath and using OVS_PACKET_CMD_EXECUTE require CAP_NET_ADMIN (GENL_UNS_ADMIN_PERM, netnsok); CAP_NET_ADMIN is obtainable inside an unprivileged user+network namespace, and TUN injection likewise requires CAP_NET_ADMIN or a TUN fd granted by a privileged setup.\nUI:N - No victim interaction is required; once OVS bridges an ARPHRD_NONE port (e.g. TUN), the attacker triggers the bug by injecting a single malformed packet via write() or netlink without any other user action.\nS:U - Impact is a kernel BUG/panic in the same kernel security authority as the attacker; this is not a VM escape, IOMMU bypass, or cross-namespace privilege boundary crossing.\nC:H - Before the BUG, key_extract() calls ether_addr_copy() and parse_ethertype() on skb-\u003edata without validating ETH_HLEN, performing out-of-bounds reads of kernel skb buffer memory beyond the actual packet payload.\nI:H - Unchecked __skb_pull() on an undersized skb corrupts skb-\u003edata and skb-\u003elen metadata; this memory corruption of kernel packet state can be leveraged for further integrity violations beyond a simple controlled crash.\nA:H - The flaw triggers kernel BUG() at __skb_pull() in include/linux/skbuff.h, producing a kernel oops/panic and denying all system availability on affected hosts running Open vSwitch with ARPHRD_NONE ports."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:41:43.778Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/e85278afd4890dd190ba3c7a1b1a712b801c9fe1"
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        {
          "url": "https://git.kernel.org/stable/c/81f9b09f0ea3ba9ab966dd17e9f32625a14555e9"
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        {
          "url": "https://git.kernel.org/stable/c/831471718f6e19aed1a330b03b53190a90e06466"
        },
        {
          "url": "https://git.kernel.org/stable/c/d8bea341b183190ce6c055ab0e64ab78eb9a7290"
        },
        {
          "url": "https://git.kernel.org/stable/c/0b60b55652ba772b173dddc63f3851e1d2dd5927"
        },
        {
          "url": "https://git.kernel.org/stable/c/a8139285c8925efe59af28a9169bb2fda91bff15"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b8cfbb58b85bfa7a78fac47fdc77396cd01f699"
        },
        {
          "url": "https://git.kernel.org/stable/c/cf6f8b29befb92173659bcef6a441d274947bfae"
        }
      ],
      "title": "net/openvswitch: check Ethernet header length in key_extract()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74701",
    "datePublished": "2026-08-22T15:33:01.585Z",
    "dateReserved": "2026-08-15T05:44:03.927Z",
    "dateUpdated": "2026-08-25T05:41:43.778Z",
    "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.

Action not permitted

GHSA-6727-4WMG-W3RC

CVE-2026-74701 (GCVE-0-2026-74701)

Tags

Sightings

Nomenclature