CVE-2026-31684 (GCVE-0-2026-31684)
Vulnerability from cvelistv5
Published
2026-04-25 08:47
Modified
2026-04-27 13:57
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.
References
Impacted products
Vendor Product Version
Linux Linux Version: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6
Version: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6
Version: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6
Version: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6
Version: 2ecba2d1e45b24620a7c3df9531895cf68d5dec6
Version: 3764bfae5056e95617b6ee074129297e11710886
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{
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          "programFiles": [
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              "version": "7.0",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: act_csum: validate nested VLAN headers\n\ntcf_csum_act() walks nested VLAN headers directly from skb-\u003edata when an\nskb still carries in-payload VLAN tags. The current code reads\nvlan-\u003eh_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without\nfirst ensuring that the full VLAN header is present in the linear area.\n\nIf only part of an inner VLAN header is linearized, accessing\nh_vlan_encapsulated_proto reads past the linear area, and the following\nskb_pull(VLAN_HLEN) may violate skb invariants.\n\nFix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and\npulling each nested VLAN header. If the header still is not fully\navailable, drop the packet through the existing error path."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-27T13:57:15.059Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2"
        },
        {
          "url": "https://git.kernel.org/stable/c/a69738efea0996d05a3c7d2178551b891744df1b"
        },
        {
          "url": "https://git.kernel.org/stable/c/ec4930979b3f7bbeb7af5744599fc6603a4dba62"
        },
        {
          "url": "https://git.kernel.org/stable/c/3d165d975305cf76ff0b10a3c798fb31e5f5f9a5"
        },
        {
          "url": "https://git.kernel.org/stable/c/c842743d073bdd683606cb414eb0ca84465dd834"
        }
      ],
      "title": "net: sched: act_csum: validate nested VLAN headers",
      "x_generator": {
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31684",
    "datePublished": "2026-04-25T08:47:01.555Z",
    "dateReserved": "2026-03-09T15:48:24.130Z",
    "dateUpdated": "2026-04-27T13:57:15.059Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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