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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Fixed version: Linux Linux 3.17, 4.17, 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3.17, 4.17, 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Aug 26, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • f6104e9ae04462523c372928b1173766a771ef95, 7f8e401f9e612df2a95c1ef76217c00181389bb5, c712ed63e9b33d9a282fbd92ce25c64918c3129f, 9a8863e8a8def9d88583cd9c60db38a008e6b8cf, 4.17affected
    • 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and later · before c38b723858a51d6ca4e56470b9f1087f23276772affected · git
    • 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and later · before bd897e414451fb34dfdf08b31899180e5ab7149baffected · git
    • 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and later · before bdf83613781956cc39798ed08321f74ab0467f4daffected · git
    • 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and later · before 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500affected · git
    • 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and later · before ebe2774e956482dd3c70b8991f6f7654356339e6affected · git
    • 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 and later · before 9006c116dd111d457bf5d074990210f70a4ad2c8affected · git
    • 3.16.60 and later · before 3.17affected · semver
    • 4.16.6 and later · before 4.17affected · semver
    • before 4.17not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.1.10-17.1.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-80583Aug 26, 2026 · ASoC: codecs: lpass-tx-macro: Fix enum kcontrol accesses
    31Monitor
  • ← EarlierCVE-2026-74734Aug 26, 2026 · firewire: ohci: fix NULL pointer dereference in ar_context_release
    0Monitor
  • Later →CVE-2026-74736Aug 26, 2026 · net/sched: cls_bpf: reject dev-bound programs bound to a different device
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3.17Vendor (CNA)
Linux Linux4.17Vendor (CNA)
Linux Linux8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500Vendor (CNA)
Linux Linux9006c116dd111d457bf5d074990210f70a4ad2c8Vendor (CNA)
Linux Linuxbd897e414451fb34dfdf08b31899180e5ab7149bVendor (CNA)
Linux Linuxbdf83613781956cc39798ed08321f74ab0467f4dVendor (CNA)
Linux Linuxc38b723858a51d6ca4e56470b9f1087f23276772Vendor (CNA)
Linux Linuxebe2774e956482dd3c70b8991f6f7654356339e6Vendor (CNA)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records