CVE-2025-40212

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2025-11-24. the CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
Trending — 5 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix refcount leak in nfsd_set_fh_dentry()

nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the various exported filesystems using LOOKUP requests from a known root filehandle. NFSv3 uses the MOUNT protocol to find those exported filesystems and so is not given access to the pseudo root filesystem.

If a v3 (or v2) client uses a filehandle from that filesystem, nfsd_set_fh_dentry() will report an error, but still stores the export in "struct svc_fh" even though it also drops the reference (exp_put()). This means that when fh_put() is called an extra reference will be dropped which can lead to use-after-free and possible denial of service.

Normal NFS usage will not provide a pseudo-root filehandle to a v3 client. This bug can only be triggered by the client synthesising an incorrect filehandle.

To fix this we move the assignments to the svc_fh later, after all possible error cases have been detected.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity98% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

November 24, 2025

Last Modified

August 5, 2026

Advisory Details (3)

Auto-updated Aug 5, 2026
No patch confirmed yet.
generic

nfsd: fix refcount leak in nfsd_set_fh_dentry() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c
generic

nfsd: fix refcount leak in nfsd_set_fh_dentry() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2
generic

nfsd: fix refcount leak in nfsd_set_fh_dentry() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b6bc86ce3944b10b9fc181fc00c1a520a20ed965

Vendor Advisories for CVE-2025-40212(1)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-azure-6.17 (6.17.0-1008.8) @ questing2026-05-21ubuntu
ubuntulinux-tools-oem-6.17 (6.17.0-1011.11) @ noble2026-05-21ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.17.0-14.14) @ questing2026-05-21ubuntu
ubuntulinux-tools-gcp-64k-6.17 (6.17.0-1007.7) @ questing2026-05-21ubuntu
ubuntulinux-tools-oracle-64k-6.17 (6.17.0-1007.7) @ questing2026-05-21ubuntu
linuxKernel @ 6.12.59—osv

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.

All Vendor Advisories

(5)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 12× in last 7d / 44× 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.

Showing the most recent 100 of 140 total refreshes for this CVE.

  1. 2026-08-05 12:51 UTCEG score recompute
  2. 2026-08-05 12:51 UTCVendor advisory
  3. 2026-08-05 12:51 UTCGHSA enrichment
  4. 2026-08-04 15:09 UTCEPSS rescore
  5. 2026-08-04 10:37 UTCEPSS rescore
  6. 2026-08-02 02:26 UTCEPSS rescore
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  8. 2026-07-30 16:27 UTCEPSS rescore
  9. 2026-07-30 06:26 UTCEG score recompute▲ 9.80
  10. 2026-07-30 06:25 UTCGHSA enrichment
  11. 2026-07-30 06:18 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  12. 2026-07-30 01:29 UTCEPSS rescore
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  14. 2026-07-27 06:39 UTCOSV refresh
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  16. 2026-07-10 00:47 UTCOSV refresh
  17. 2026-07-09 19:09 UTCEPSS rescore
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  47. 2026-06-21 11:31 UTCOSV refresh
  48. 2026-06-21 01:59 UTCEPSS rescore
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  50. 2026-06-19 19:25 UTCEPSS rescore
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  75. 2026-06-02 04:09 UTCOSV refresh

Related CVEs(same product + same vendor)

Frequently asked(5)

What is CVE-2025-40212?
CVE-2025-40212 is a critical vulnerability published on November 24, 2025. In the Linux kernel, the following vulnerability has been resolved: nfsd: fix refcount leak in nfsdsetfh_dentry() nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the various exported filesystems using LOOKUP requests from a known root filehandle. NFSv3 uses the MOUNT protocol…
When was CVE-2025-40212 disclosed?
CVE-2025-40212 was first published in the National Vulnerability Database on November 24, 2025, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-40212 actively exploited?
CVE-2025-40212 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 68.1% of all scored CVEs.
What is the CVSS score of CVE-2025-40212?
CVE-2025-40212 has a CVSS v4.0 base score of 9.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2025-40212?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-40212, 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.

Dependency Blast Radius

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