CVE Intelligence
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CVE-2026-74735 — l2tp: fix tunnel and session refcount leak on seq_file release

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.

Published Aug 26, 2026 · Updated Oct 21, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.18%
ahead of 7% of scored CVEs · Oct 26, 2026
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and < bdf83613781956cc39798ed08321f74ab0467f4d≥ 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and < 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500≥ 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and < ebe2774e956482dd3c70b8991f6f7654356339e6≥ 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and < 9006c116dd111d457bf5d074990210f70a4ad2c8version f6104e9ae04462523c372928b1173766a771ef95version 7f8e401f9e612df2a95c1ef76217c00181389bb5version c712ed63e9b33d9a282fbd92ce25c64918c3129fversion 9a8863e8a8def9d88583cd9c60db38a008e6b8cf
and 4 more ≥ 3.16.60 and < 3.17≥ 4.16.6 and < 4.17version 4.17≥ 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and < bd897e414451fb34dfdf08b31899180e5ab7149b
Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 26, 2026 · 11 reading(s) · max 0.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · linux/linux
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Aug 26, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 21, 2026 – Oct 21, 2026
  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

7 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99092 riscv: patch: fix handling of bpf-jit execmem addresses 23h
  • CVE-2026-99093 mm: don't schedule deferred kernel page table freeing while booting 23h
  • CVE-2026-99095 drm/vc4: drain the hangcheck timer and works on V3D unbind 23h
  • CVE-2026-99096 io_uring/register: don't exempt disabled rings from task restrictions 23h
  • CVE-2026-99097 tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper() 23h
  • CVE-2026-99098 dm-integrity: fix buffer overflow in inline mode with large tag size 23h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-74735 is "l2tp: fix tunnel and session refcount leak on seq_file release", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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