CVE-2026-52981 (GCVE-0-2026-52981)
Vulnerability from cvelistv5
Published
2026-06-24 16:28
Modified
2026-08-05 12:32
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: neigh: let neigh_xmit take skb ownership neigh_xmit always releases the skb, except when no neighbour table is found. But even the first added user of neigh_xmit (mpls) relied on neigh_xmit to release the skb (or queue it for tx). sashiko reported: If neigh_xmit() is called with an uninitialized neighbor table (for example, NEIGH_ND_TABLE when IPv6 is disabled), it returns -EAFNOSUPPORT and bypasses its internal out_kfree_skb error path. Because the return value of neigh_xmit() is ignored here, does this leak the SKB? Assume full ownership and remove the last code path that doesn't xmit or free skb.
References
Impacted products
Vendor Product Version
Linux Linux Version: 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62
Version: 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62
Version: 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62
Version: 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62
Version: 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62
Version: 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62
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{
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          "programFiles": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nneigh: let neigh_xmit take skb ownership\n\nneigh_xmit always releases the skb, except when no neighbour table is\nfound. But even the first added user of neigh_xmit (mpls) relied on\nneigh_xmit to release the skb (or queue it for tx).\n\nsashiko reported:\n If neigh_xmit() is called with an uninitialized neighbor table (for\n example, NEIGH_ND_TABLE when IPv6 is disabled), it returns -EAFNOSUPPORT\n and bypasses its internal out_kfree_skb error path.  Because the return\n value of neigh_xmit() is ignored here, does this leak the SKB?\n\nAssume full ownership and remove the last code path that doesn\u0027t\nxmit or free skb."
        }
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            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
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              "value": "AV:N - An unauthenticated packet sender can trigger the vulnerable `neigh_xmit()` path through configured network forwarding paths such as nftables netdev forwarding or MPLS forwarding. In the highest reasonable deployment, this is an exposed router/firewall datapath reachable by network traffic.\nAC:L - The bug is deterministic once the forwarding path uses a real neighbor table whose pointer is NULL, such as `NEIGH_ND_TABLE` when IPv6 neighbor discovery is unavailable. No race or heap shaping is required; repeated matching packets repeatedly leak skbs.\nPR:N - The attacker does not need privileges to send packets into an already configured vulnerable forwarding datapath. Although installing such rules/routes requires administrative network privileges, the packet-triggering attack itself is unauthenticated.\nUI:N - No victim user action is required after the affected forwarding configuration exists. The attacker only sends traffic that reaches the vulnerable path.\nS:U - The impact remains within the kernel/networking security authority of the affected system. There is no VM escape, sandbox boundary crossing, or separate security scope involved.\nC:N - The flaw is an skb memory leak caused by failing to free the packet buffer on the missing-table error path. It does not expose leaked memory contents to the attacker.\nI:N - The bug does not provide a memory corruption or data modification primitive. It only loses ownership of allocated skbs.\nA:H - An attacker can repeatedly trigger the leak with packets, consuming kernel memory and plausibly causing OOM, hangs, packet processing failure, or system-wide denial of service. Kernel memory exhaustion is a high availability impact."
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:32:19.237Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/8a89054a1ec0767aec25ed2bbac933da6ba3cf5a"
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          "url": "https://git.kernel.org/stable/c/445e45a2c3a078316a62d2d331a570cf34ef5079"
        },
        {
          "url": "https://git.kernel.org/stable/c/4438113be604ee67a7bf4f81da6e1cca41332ce4"
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      ],
      "title": "neigh: let neigh_xmit take skb ownership",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-52981",
    "datePublished": "2026-06-24T16:28:57.074Z",
    "dateReserved": "2026-06-09T07:44:35.376Z",
    "dateUpdated": "2026-08-05T12:32:19.237Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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