CVE-2026-64594

Kernel warning via uninitialized FunctionFS reset work

Published Aug 6, 2026 · Updated Aug 6, 2026

Improper initialization in Linux FunctionFS 4.0 and later allows local users to trigger a kernel warning by unmounting an instance. ffs_data_new() zero-allocates reset_work without INIT_WORK(), while ffs_fs_kill_sb() always passes it to cancel_work_sync(), reaching WARN_ON with a NULL work function. Triggering the path requires CAP_SYS_ADMIN to unmount FunctionFS; the published consequence is the warning, with no reported data access, privilege gain, or unconditional service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper initialization in Linux FunctionFS 4.0 and later allows local users to trigger a kernel warning by unmounting an instance. ffs_data_new() zero-allocates reset_work without INIT_WORK(), while ffs_fs_kill_sb() always passes it to cancel_work_sync(), reaching WARN_ON with a NULL work function. Triggering the path requires CAP_SYS_ADMIN to unmount FunctionFS; the published consequence is the warning, with no reported data access, privilege gain, or unconditional service interruption.

The record

CVE
CVE-2026-64594
Published
Aug 6, 2026
Updated
Aug 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <0de6ebbabfbbc9c28350283dc97d8a519d5c6dd7
  2. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <3137b243c93982fe3460335e12f9247739766e10
  3. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <69faa3779250df14f51d5084f938a99809546e52
  4. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <7fe895e0a9651518c4fc082487da770ff9c14c7f
  5. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <ba1867999dbc4085e6d8c52ac5266005b8b2bf07
  6. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <c36393b0d14e1e9783888f821ffe29381b8f46dc
  7. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <cb19e54ebe9baf3c3243083ade65c937339ccb7b
  8. Affected versionversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <d5631081be07f20e764d3cb5c98ac0a1004fba51
  9. Affected versionversion=4.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=18d6b32fca3841f7cd9479b4024abd8a9b299281 <0de6ebbabfbbc9c28350283dc97d8a519d5c6dd7; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <3137b243c93982fe3460335e12f9247739766e10; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <69faa3779250df14f51d5084f938a99809546e52; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <7fe895e0a9651518c4fc082487da770ff9c14c7f; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <ba1867999dbc4085e6d8c52ac5266005b8b2bf07; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <c36393b0d14e1e9783888f821ffe29381b8f46dc; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <cb19e54ebe9baf3c3243083ade65c937339ccb7b; version=18d6b32fca3841f7cd9479b4024abd8a9b299281 <d5631081be07f20e764d3cb5c98ac0a1004fba51; version=4.0

Published CVSS scores

No CVSS assessment is available in this record.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo