CVE-2026-90420Public exploit

Filesystem hang via endless cleaner error retries

Published Sep 17, 2026 · Updated Sep 17, 2026

An infinite loop in Linux NILFS2 allows local users to hang filesystem operations via the privileged segment-cleaning ioctl. In fs/nilfs2/segment.c, nilfs_clean_segments() logs errors and sleeps instead of terminating when nilfs_segctor_construct() repeatedly returns -EROFS. The ioctl requires CAP_SYS_ADMIN and an active NILFS2 filesystem; a read-only transition during cleaning, such as after an I/O error, leaves the cleaner looping and dependent transactions blocked.

CVSS severity4.1
Medium
EPSS probability0.22%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An infinite loop in Linux NILFS2 allows local users to hang filesystem operations via the privileged segment-cleaning ioctl. In fs/nilfs2/segment.c, nilfs_clean_segments() logs errors and sleeps instead of terminating when nilfs_segctor_construct() repeatedly returns -EROFS. The ioctl requires CAP_SYS_ADMIN and an active NILFS2 filesystem; a read-only transition during cleaning, such as after an I/O error, leaves the cleaner looping and dependent transactions blocked.

The record

CVE
CVE-2026-90420
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=2.6.30
  2. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <1fc6df85b4954b6fda9c351843aaca3c06f66d8d
  3. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <217b967ad7887a3e1ebc08f46f6484e081acd4b4
  4. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <3bcdbdaac884a4baa59716cf9bd9470c75276e2d
  5. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <8cea0bc78ac64cb88da49c07f80bf2cf9fb7aff8
  6. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <c07e5ad6539e7e9350d5c65cbf8adb69d1711b15
  7. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <ce5a5ad1a8330a2fcfdd9ec2ab341be739e89a18
  8. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <d7afca8e4efbf4c455b4663c29ae59fde2f1b671
  9. Affected versionversion=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <e3e9367dae1a6392cbb14ab0b2ab5edbf39735c3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.30; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <1fc6df85b4954b6fda9c351843aaca3c06f66d8d; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <217b967ad7887a3e1ebc08f46f6484e081acd4b4; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <3bcdbdaac884a4baa59716cf9bd9470c75276e2d; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <8cea0bc78ac64cb88da49c07f80bf2cf9fb7aff8; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <c07e5ad6539e7e9350d5c65cbf8adb69d1711b15; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <ce5a5ad1a8330a2fcfdd9ec2ab341be739e89a18; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <d7afca8e4efbf4c455b4663c29ae59fde2f1b671; version=9ff05123e3bfbb1d2b68ba1d9bf1f7d1dffc1453 <e3e9367dae1a6392cbb14ab0b2ab5edbf39735c3

Published CVSS scores

4.1SUSECVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
4.1Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

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No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

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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