CVE-2009-3726

HIGHCVSS v2 · 7.87.8—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 7.8 — v2 rates that HIGH (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:N/AC:L/Au:N/C:N/I:N/A:C. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 12.0% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.

Sources: epss, nvd_v2
Weaponized
7.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • Public exploit code is available (Exploit-DB (verified), epss top5pct, public exploit)
CISA-KEV: Not listedEPSS PROB: 12%CVSS v2: 7.8Exploit: Exploit-DB (verified) · epss top5pct · public exploitExposed: 0

A fix is available — apply it.

The nfs4_proc_lock function in fs/nfs/nfs4proc.c in the NFSv4 client in the Linux kernel before 2.6.31-rc4 allows remote NFS servers to cause a denial of service (NULL pointer dereference and panic) by sending a certain response containing incorrect file attributes, which trigger attempted use of an open file that lacks NFSv4 state.

CVSS v2.0 (legacy)
7.8HIGHNVD never assigned a CVSS v3 rating to this CVE
EG Score
7.8(low)
EG Risk
66(Track)
EG Risk 66/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation65% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
12%
EPSS %ILE
96%
KEV
Not listed

Published

November 9, 2009

Last Modified

April 23, 2026

References (50)

Vendor Advisories for CVE-2009-3726(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-2.6.31-16-powerpc (2.6.31-16.52) @ karmic2026-05-30ubuntu
redhatkernel-0:2.6.9-89.0.26.EL2010-06-15redhat
redhatkernel-0:2.6.18-164.9.1.el52009-12-15redhat
redhatkernel-rt-0:2.6.24.7-139.el5rt2009-12-03redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
Debian:4.0(2)
PackageVulnerable rangeFixed inDependents
linux-2.62.6.18.dfsg.1-12 ... 2.6.18.dfsg.1-26etch1 (38 versions)2.6.18.dfsg.1-26etch2—
linux-2.6.242.6.24-5~etchnhalf.1 ... 2.6.24-6~etchnhalf.9etch2 (15 versions)2.6.24-6~etchnhalf.9etch3—

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 2× in last 7d / 8× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-25 13:43 UTCEPSS rescore
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  9. 2026-07-26 13:39 UTCEG score recompute▲ 7.80
  10. 2026-07-25 14:12 UTCEPSS rescore
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  13. 2026-07-23 01:00 UTCEG score recompute
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  56. 2026-05-30 14:40 UTCEG score recompute
  57. 2026-05-30 14:40 UTCVendor advisory
  58. 2026-05-30 14:40 UTCGHSA enrichment
  59. 2026-05-29 13:40 UTCEPSS rescore
  60. 2026-05-28 13:42 UTCEPSS rescore
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Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-10202✓ verified
    First seen Oct 15, 2009

    Linux Kernel < 2.6.31-rc4 - 'nfs4_proc_lock()' Denial of Service

    Open source ↗

Frequently asked(4)

What is CVE-2009-3726?
CVE-2009-3726 is a high vulnerability published on November 9, 2009. The nfs4proclock function in fs/nfs/nfs4proc.c in the NFSv4 client in the Linux kernel before 2.6.31-rc4 allows remote NFS servers to cause a denial of service (NULL pointer dereference and panic) by sending a certain response containing incorrect file attributes, which trigger attempted use of an…
When was CVE-2009-3726 disclosed?
CVE-2009-3726 was first published in the National Vulnerability Database on November 9, 2009, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-3726 actively exploited?
CVE-2009-3726 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 12% probability of exploitation in the next 30 days, which ranks it in the top 4.2% of all scored CVEs.
How do I remediate CVE-2009-3726?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-3726, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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