CVE-2026-23018

Local service hang via btrfs lock inversion

Published Jan 31, 2026 · Updated Jan 31, 2026

Deadlock in Linux Kernel 6.16.9 through 6.18.5 allows local users to hang systems by opening an inode on a btrfs subvolume. btrfs_read_locked_inode() calls btrfs_init_file_extent_tree() while retaining a subvolume-tree leaf read lock, and its GFP_KERNEL allocation can enter reclaim and complete a circular dependency with the delayed-node mutex. A local low-privileged user must reach an inode on an affected btrfs subvolume; successful exploitation blocks kernel progress and interrupts service.

CVSS severity5.5
Medium
EPSS probability0.10%
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

Deadlock in Linux Kernel 6.16.9 through 6.18.5 allows local users to hang systems by opening an inode on a btrfs subvolume. btrfs_read_locked_inode() calls btrfs_init_file_extent_tree() while retaining a subvolume-tree leaf read lock, and its GFP_KERNEL allocation can enter reclaim and complete a circular dependency with the delayed-node mutex. A local low-privileged user must reach an inode on an affected btrfs subvolume; successful exploitation blocks kernel progress and interrupts service.

The record

CVE
CVE-2026-23018
Published
Jan 31, 2026
Updated
Jan 31, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 31, 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=6.17
  2. Affected versionversion=8679d2687c351824d08cf1f0e86f3b65f22a00fe <8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347
  3. Affected versionversion=8679d2687c351824d08cf1f0e86f3b65f22a00fe <92a5590851144f034adc51fee55e6878ccac716e
  4. Affected versionversion=e8f496001e0c7832d188ab91fea294e19a128202

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.17; version=8679d2687c351824d08cf1f0e86f3b65f22a00fe <8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347; version=8679d2687c351824d08cf1f0e86f3b65f22a00fe <92a5590851144f034adc51fee55e6878ccac716e; version=e8f496001e0c7832d188ab91fea294e19a128202

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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