---
id: CVE-2026-74735
title: |-
  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…
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…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 <
    bdf83613781956cc39798ed08321f74ab0467f4d
  - >-
    Linux >= 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 <
    8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500
  - >-
    Linux >= 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 <
    ebe2774e956482dd3c70b8991f6f7654356339e6
  - >-
    Linux >= 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 <
    9006c116dd111d457bf5d074990210f70a4ad2c8
  - Linux f6104e9ae04462523c372928b1173766a771ef95
  - Linux 7f8e401f9e612df2a95c1ef76217c00181389bb5
  - Linux c712ed63e9b33d9a282fbd92ce25c64918c3129f
  - Linux 9a8863e8a8def9d88583cd9c60db38a008e6b8cf
  - Linux >= 3.16.60 < 3.17
  - Linux >= 4.16.6 < 4.17
  - Linux 4.17
published: '2026-08-26'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T14:17:20.040'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74735'
references:
  - url: 'https://git.kernel.org/stable/c/8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9006c116dd111d457bf5d074990210f70a4ad2c8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bdf83613781956cc39798ed08321f74ab0467f4d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ebe2774e956482dd3c70b8991f6f7654356339e6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00175
epssPercentile: 0.07294
ingestedAt: '2026-09-21T13:37:22.838Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.