CVE-2025-40273Network attack vector

Server crash via stale copynotify stateid cleanup

Published Dec 6, 2025 · Updated Aug 5, 2026

Use-after-free in affected Linux kernel NFSD releases allows remote authenticated users to crash NFS servers through NFSv4.2 requests. nfs4_free_ol_stateid() frees a parent open stateid without first freeing its associated copynotify stateid, leaving a stale list entry that nfsd4_laundromat later deletes from reused kernel memory. The attacker must hold valid NFSv4.2 open state and drive OPEN, COPY_NOTIFY, client restart, and CREATE_SESSION; cleanup then produces list corruption and a kernel oops or panic.

CVSS severity8.8
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in affected Linux kernel NFSD releases allows remote authenticated users to crash NFS servers through NFSv4.2 requests. nfs4_free_ol_stateid() frees a parent open stateid without first freeing its associated copynotify stateid, leaving a stale list entry that nfsd4_laundromat later deletes from reused kernel memory. The attacker must hold valid NFSv4.2 open state and drive OPEN, COPY_NOTIFY, client restart, and CREATE_SESSION; cleanup then produces list corruption and a kernel oops or panic.

The record

CVE
CVE-2025-40273
Published
Dec 6, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 6, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.6
  2. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <29fbb3ad4018ca2b0988fbac76f4c694cc6d7e66
  3. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <4aa17144d5abc3c756883e3a010246f0dba8b468
  4. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <839f56f626723f36904764858467e7a3881b975d
  5. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <935a2dc8928670bb2c37e21025331e61ec48ccf4
  6. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <b114996a095da39e38410a0328d4a8aca8c36088
  7. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <d7be15a634aa3874827d0d3ea47452ee878b8df7
  8. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <f67ad9b33b0e6f00d2acc67cbf9cfa5c756be5fb

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=624322f1adc58acd0b69f77a6ddc764207e97241 <29fbb3ad4018ca2b0988fbac76f4c694cc6d7e66; version=624322f1adc58acd0b69f77a6ddc764207e97241 <4aa17144d5abc3c756883e3a010246f0dba8b468; version=624322f1adc58acd0b69f77a6ddc764207e97241 <839f56f626723f36904764858467e7a3881b975d; version=624322f1adc58acd0b69f77a6ddc764207e97241 <935a2dc8928670bb2c37e21025331e61ec48ccf4; version=624322f1adc58acd0b69f77a6ddc764207e97241 <b114996a095da39e38410a0328d4a8aca8c36088; version=624322f1adc58acd0b69f77a6ddc764207e97241 <d7be15a634aa3874827d0d3ea47452ee878b8df7; version=624322f1adc58acd0b69f77a6ddc764207e97241 <f67ad9b33b0e6f00d2acc67cbf9cfa5c756be5fb

Published CVSS scores

8.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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