CVE-2026-90261Hinoki check available

Write interruption via zoned metadata writeback ordering

Published Sep 17, 2026 · Updated Sep 17, 2026

Writeback failure in Linux Btrfs 6.6 allows local users to interrupt filesystem writes via metadata relocation on zoned storage. In fs/btrfs/extent_io.c, btree_writepages() visits lower-address dirty metadata before flushing the higher-address active block group; btrfs_write_and_wait_transaction() treats the resulting -EAGAIN as fatal. The failure requires zoned Btrfs and occurs intermittently during metadata-heavy relocation, aborting the transaction and forcing the filesystem read-only rather than crashing the host.

CVSS severity2.5
Low
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Writeback failure in Linux Btrfs 6.6 allows local users to interrupt filesystem writes via metadata relocation on zoned storage. In fs/btrfs/extent_io.c, btree_writepages() visits lower-address dirty metadata before flushing the higher-address active block group; btrfs_write_and_wait_transaction() treats the resulting -EAGAIN as fatal. The failure requires zoned Btrfs and occurs intermittently during metadata-heavy relocation, aborting the transaction and forcing the filesystem read-only rather than crashing the host.

The record

CVE
CVE-2026-90261
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

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=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <e2de2989adb3e58c2320e57c255f52e065667b5e
  2. Affected versionversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <ecc05eda9a346848ae01a6c8bfa3f0bec133bd8b
  3. Affected versionversion=6.5.5 <6.6
  4. Affected versionversion=6.6
  5. Affected versionversion=fca3a1cd3ba47f1815e0c0fcdc9aafaf02ee0a75

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <e2de2989adb3e58c2320e57c255f52e065667b5e; version=13bb483d32abb6f8ebd40141d87eb68f11cc2dd2 <ecc05eda9a346848ae01a6c8bfa3f0bec133bd8b; version=6.5.5 <6.6; version=6.6; version=fca3a1cd3ba47f1815e0c0fcdc9aafaf02ee0a75

Published CVSS scores

5.5TenableCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5TenableCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.5Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
4.6TenableAV:L/AC:L/Au:S/C:N/I:N/A:C

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
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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