CVE-2026-74735 (GCVE-0-2026-74735)
Vulnerability from cvelistv5
Published
2026-08-26 14:36
Modified
2026-08-26 14:36
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: l2tp: fix tunnel and session refcount leak on seq_file release In pppol2tp_proc_open() and l2tp_dfs_seq_open(), iteration state (pd->tunnel and pd->session) is kept in seq_file private data to allow iteration across multiple read() system calls. However, if userspace closes /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels before reading to end-of-file (EOF), any tunnel or session reference stored in pd->tunnel / pd->session is left un-dropped when seq_file private data is freed. Fix this by dropping any remaining pd->tunnel and pd->session references in pppol2tp_proc_release() and l2tp_dfs_seq_release() when closing the file.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443
Version: 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443
Version: f6104e9ae04462523c372928b1173766a771ef95
Version: 7f8e401f9e612df2a95c1ef76217c00181389bb5
Version: c712ed63e9b33d9a282fbd92ce25c64918c3129f
Version: 9a8863e8a8def9d88583cd9c60db38a008e6b8cf
Version: 3.16.60   ≤
Version: 4.16.6   ≤
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{
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      "affected": [
        {
          "defaultStatus": "unaffected",
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          "programFiles": [
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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\nl2tp: fix tunnel and session refcount leak on seq_file release\n\nIn pppol2tp_proc_open() and l2tp_dfs_seq_open(), iteration state\n(pd-\u003etunnel and pd-\u003esession) is kept in seq_file private data to allow\niteration across multiple read() system calls.\n\nHowever, if userspace closes /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels\nbefore reading to end-of-file (EOF), any tunnel or session reference stored in\npd-\u003etunnel / pd-\u003esession is left un-dropped when seq_file private data is freed.\n\nFix this by dropping any remaining pd-\u003etunnel and pd-\u003esession references in\npppol2tp_proc_release() and l2tp_dfs_seq_release() when closing the file."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-26T14:36:49.352Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/ebe2774e956482dd3c70b8991f6f7654356339e6"
        },
        {
          "url": "https://git.kernel.org/stable/c/9006c116dd111d457bf5d074990210f70a4ad2c8"
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      ],
      "title": "l2tp: fix tunnel and session refcount leak on seq_file release",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74735",
    "datePublished": "2026-08-26T14:36:49.352Z",
    "dateReserved": "2026-08-15T05:44:03.930Z",
    "dateUpdated": "2026-08-26T14:36:49.352Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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