CVE-2026-99132Public exploit

Filesystem hang via label-update lock deadlock

Published Oct 28, 2026 · Updated Oct 28, 2026

Deadlock in Linux XFS allows local users to hang filesystem operations via a label update concurrent with filesystem shutdown. The xfs_sync_sb_buf() function retains superblock buffer locks while synchronous transaction commit waits for CIL work whose shutdown path needs those same locks. The label-update ioctl requires CAP_SYS_ADMIN and a writable mounted XFS filesystem; the documented consequence is blocked tasks, not code execution.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in Linux XFS allows local users to hang filesystem operations via a label update concurrent with filesystem shutdown. The xfs_sync_sb_buf() function retains superblock buffer locks while synchronous transaction commit waits for CIL work whose shutdown path needs those same locks. The label-update ioctl requires CAP_SYS_ADMIN and a writable mounted XFS filesystem; the documented consequence is blocked tasks, not code execution.

The record

CVE
CVE-2026-99132
Published
Oct 28, 2026
Updated
Oct 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Oct 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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=4.18
  2. Affected versionversion=f7664b31975bd893190708e76b2c424328f0c49b <41a28c865d1d5843f8cb9e0af17a8f4d9e2961ff
  3. Affected versionversion=f7664b31975bd893190708e76b2c424328f0c49b <6353e5cd8c43d6e805cacbfbfecf4103571a7ff8
  4. Affected versionversion=f7664b31975bd893190708e76b2c424328f0c49b <e5456dec79c71c8ef8f9f9adb77d320f113b34db

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=4.18; version=f7664b31975bd893190708e76b2c424328f0c49b <41a28c865d1d5843f8cb9e0af17a8f4d9e2961ff; version=f7664b31975bd893190708e76b2c424328f0c49b <6353e5cd8c43d6e805cacbfbfecf4103571a7ff8; version=f7664b31975bd893190708e76b2c424328f0c49b <e5456dec79c71c8ef8f9f9adb77d320f113b34db

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.

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

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

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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