CVE-2025-40007

Service hangs via leaked netfs request reference

Published Oct 20, 2025 · Updated Oct 20, 2025

Reference leak in Linux kernel netfs allows local users to hang filesystem-dependent services after an early I/O submission failure. Early error paths decrement a two-reference netfs_io_request only once, while the unqueued completion worker never releases the remaining reference. Reachability requires a netfs operation to fail before submission; the retained request keeps netfs_inode.io_count positive and can deadlock Ceph workloads.

CVSS severity6.8
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference leak in Linux kernel netfs allows local users to hang filesystem-dependent services after an early I/O submission failure. Early error paths decrement a two-reference netfs_io_request only once, while the unqueued completion worker never releases the remaining reference. Reachability requires a netfs operation to fail before submission; the retained request keeps netfs_inode.io_count positive and can deadlock Ceph workloads.

The record

CVE
CVE-2025-40007
Published
Oct 20, 2025
Updated
Oct 20, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 20, 2025Record 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=1a8360c2eed3b292ed654c2ac61b09de4a80e298
  2. Affected versionversion=20d72b00ca814d748f5663484e5c53bb2bf37a3a <4d428dca252c858bfac691c31fa95d26cd008706
  3. Affected versionversion=20d72b00ca814d748f5663484e5c53bb2bf37a3a <8df142e93098b4531fadb5dfcf93087649f570b3
  4. Affected versionversion=6.16

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1a8360c2eed3b292ed654c2ac61b09de4a80e298; version=20d72b00ca814d748f5663484e5c53bb2bf37a3a <4d428dca252c858bfac691c31fa95d26cd008706; version=20d72b00ca814d748f5663484e5c53bb2bf37a3a <8df142e93098b4531fadb5dfcf93087649f570b3; version=6.16

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
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.

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Technologies

Your stack

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Your stack

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