CVE-2023-53698 (GCVE-0-2023-53698)
Vulnerability from cvelistv5
Published
2025-10-22 13:23
Modified
2026-08-05 09:15
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: xsk: fix refcount underflow in error path Fix a refcount underflow problem reported by syzbot that can happen when a system is running out of memory. If xp_alloc_tx_descs() fails, and it can only fail due to not having enough memory, then the error path is triggered. In this error path, the refcount of the pool is decremented as it has incremented before. However, the reference to the pool in the socket was not nulled. This means that when the socket is closed later, the socket teardown logic will think that there is a pool attached to the socket and try to decrease the refcount again, leading to a refcount underflow. I chose this fix as it involved adding just a single line. Another option would have been to move xp_get_pool() and the assignment of xs->pool to after the if-statement and using xs_umem->pool instead of xs->pool in the whole if-statement resulting in somewhat simpler code, but this would have led to much more churn in the code base perhaps making it harder to backport.
References
Impacted products
Vendor Product Version
Linux Linux Version: f7019562f142bc041f9cde63af338d1886585923
Version: ba3beec2ec1d3b4fd8672ca6e781dac4b3267f6e
Version: ba3beec2ec1d3b4fd8672ca6e781dac4b3267f6e
Version: ba3beec2ec1d3b4fd8672ca6e781dac4b3267f6e
Version: 9f0c8a9d4ef1b9ebee0e4ac2495fe790727044aa
Version: 5.15.47   ≤
Version: 5.17.15   ≤
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      "cpeApplicability": [
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          "nodes": [
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxsk: fix refcount underflow in error path\n\nFix a refcount underflow problem reported by syzbot that can happen\nwhen a system is running out of memory. If xp_alloc_tx_descs() fails,\nand it can only fail due to not having enough memory, then the error\npath is triggered. In this error path, the refcount of the pool is\ndecremented as it has incremented before. However, the reference to\nthe pool in the socket was not nulled. This means that when the socket\nis closed later, the socket teardown logic will think that there is a\npool attached to the socket and try to decrease the refcount again,\nleading to a refcount underflow.\n\nI chose this fix as it involved adding just a single line. Another\noption would have been to move xp_get_pool() and the assignment of\nxs-\u003epool to after the if-statement and using xs_umem-\u003epool instead of\nxs-\u003epool in the whole if-statement resulting in somewhat simpler code,\nbut this would have led to much more churn in the code base perhaps\nmaking it harder to backport."
        }
      ],
      "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 vulnerability is reached through the AF_XDP `socket()`/`setsockopt()`/`bind()` syscall interface, a purely local kernel API with no network exposure.\nAC:L - The attacker controls both sockets and the Tx-ring allocation size, and can induce memory pressure and recreate the pool to retry, making the required allocation failure inducible and repeatable.\nPR:L - Creating the AF_XDP socket requires CAP_NET_RAW, but this is checked against `net-\u003euser_ns`, so an unprivileged local user obtains it via an unprivileged user+network namespace (`unshare -Urn`).\nUI:N - The attacker performs all socket setup, binding, and teardown steps itself; no action by another user is required.\nS:U - The corruption is confined to the kernel\u0027s own buffer-pool objects within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The premature free produces a use-after-free of the `xsk_buff_pool`; a reclaimed-and-sprayed allocation lets the attacker read freed-object contents, yielding arbitrary kernel memory disclosure.\nI:H - The use-after-free/double-free of the pool provides a write primitive (dangling refcount and pool fields) exploitable via heap spraying for kernel memory corruption and control-flow hijacking.\nA:H - The refcount underflow frees a pool still in use by another socket, reliably causing use-after-free memory corruption, oops, or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T09:15:36.147Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/789fcd94c9cac133dd4d96e193188661aca9f6c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/15b453cf7348973217558235b9ece2ee5fea6777"
        },
        {
          "url": "https://git.kernel.org/stable/c/3e7722c31d4167eb7f3ffd35aba52cab69b79072"
        },
        {
          "url": "https://git.kernel.org/stable/c/85c2c79a07302fe68a1ad5cc449458cc559e314d"
        }
      ],
      "title": "xsk: fix refcount underflow in error path",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53698",
    "datePublished": "2025-10-22T13:23:38.384Z",
    "dateReserved": "2025-10-22T13:21:37.345Z",
    "dateUpdated": "2026-08-05T09:15:36.147Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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