CVE-2026-74735

l2tp: fix tunnel and session refcount leak on seq_file release

N/A
Published: August 26, 2026 at 02:36 PM UTC
Updated: October 21, 2026 at 01:19 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
N/A
Exploit prediction
EPSS 0.2%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0e0c3fee3a59a387aeecc4fca6f3a2e9615a54433.16.604.16.64.177f8e401f9e612df2a95c1ef76217c00181389bb59a8863e8a8def9d88583cd9c60db38a008e6b8cfc712ed63e9b33d9a282fbd92ce25c64918c3129ff6104e9ae04462523c372928b1173766a771ef95
Vendor states this is fixed in 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500 (fixed)
Vendor states this is fixed in 9006c116dd111d457bf5d074990210f70a4ad2c8 (fixed)
Vendor states this is fixed in bdf83613781956cc39798ed08321f74ab0467f4d (fixed)
Vendor states this is fixed in ebe2774e956482dd3c70b8991f6f7654356339e6 (fixed)
Affected range stops below 3.17, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 4.17 (unaffected)
Vendor states this is fixed in 6.12.111 (unaffected)
Vendor states this is fixed in 6.18.53 (unaffected)
Vendor states this is fixed in 6.6.160 (unaffected)
Vendor states this is fixed in 7.1.10 (unaffected)
Vendor states this is fixed in 7.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

Quick Info

StatusRECEIVED

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