CVE-2026-74735 (GCVE-0-2026-74735)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:36 – Updated: 2026-08-26 14:36
VLAI
Title
l2tp: fix tunnel and session refcount leak on seq_file release
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 , < ebe2774e956482dd3c70b8991f6f7654356339e6 (git)
Affected: 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 , < 9006c116dd111d457bf5d074990210f70a4ad2c8 (git)
Affected: f6104e9ae04462523c372928b1173766a771ef95 (git)
Affected: 7f8e401f9e612df2a95c1ef76217c00181389bb5 (git)
Affected: c712ed63e9b33d9a282fbd92ce25c64918c3129f (git)
Affected: 9a8863e8a8def9d88583cd9c60db38a008e6b8cf (git)
Affected: 3.16.60 , < 3.17 (semver)
Affected: 4.16.6 , < 4.17 (semver)
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Linux Linux Affected: 4.17
Unaffected: 0 , < 4.17 (semver)
Unaffected: 7.1.10 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "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",
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        "shortName": "Linux"
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    "datePublished": "2026-08-26T14:36:49.352Z",
    "dateReserved": "2026-08-15T05:44:03.930Z",
    "dateUpdated": "2026-08-26T14:36:49.352Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-01T10:38:14+00:00",
      "cve": "CVE-2026-74735",
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      "initial_release_date": "2026-08-26T00:00:00+00:00",
      "product_status:known_affected": "232",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: l2tp: fix tunnel and session refcount leak on seq_file release",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74735.json",
      "version": "3"
    }
  }
}



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