CVE-2024-26671

I/O hang via blk-mq waiter race

Published Apr 2, 2024 · Updated May 11, 2026

Race condition in the Linux kernel blk-mq subsystem allows local users to hang block I/O by exhausting available driver tags. A missing ordering barrier in blk_mq_mark_tag_wait permits a driver-tag retry to occur before its wait-queue entry is globally visible, so __sbitmap_queue_wake_up can observe no waiter and issue no wakeup. Reaching the race requires local I/O load and driver-tag exhaustion; the demonstrated consequence is an I/O hang rather than data disclosure or modification.

CVSS severity4.7
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the Linux kernel blk-mq subsystem allows local users to hang block I/O by exhausting available driver tags. A missing ordering barrier in blk_mq_mark_tag_wait permits a driver-tag retry to occur before its wait-queue entry is globally visible, so __sbitmap_queue_wake_up can observe no waiter and issue no wakeup. Reaching the race requires local I/O load and driver-tag exhaustion; the demonstrated consequence is an I/O hang rather than data disclosure or modification.

The record

CVE
CVE-2024-26671
Published
Apr 2, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 2, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=4.11
  2. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <1d9c777d3e70bdc57dddf7a14a80059d65919e56
  3. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <5266caaf5660529e3da53004b8b7174cab6374ed
  4. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <6d8b01624a2540336a32be91f25187a433af53a0
  5. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <7610ba1319253225a9ba8a9d28d472fc883b4e2f
  6. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <89e0e66682e1538aeeaa3109503473663cd24c8b
  7. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <9525b38180e2753f0daa1a522b7767a2aa969676
  8. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <ecd7744a1446eb02ccc63e493e2eb6ede4ef1e10
  9. Affected versionversion=da55f2cc78418dee88400aafbbaed19d7ac8188e <f1bc0d8163f8ee84a8d5affdf624cfad657df1d2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.11; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <1d9c777d3e70bdc57dddf7a14a80059d65919e56; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <5266caaf5660529e3da53004b8b7174cab6374ed; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <6d8b01624a2540336a32be91f25187a433af53a0; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <7610ba1319253225a9ba8a9d28d472fc883b4e2f; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <89e0e66682e1538aeeaa3109503473663cd24c8b; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <9525b38180e2753f0daa1a522b7767a2aa969676; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <ecd7744a1446eb02ccc63e493e2eb6ede4ef1e10; version=da55f2cc78418dee88400aafbbaed19d7ac8188e <f1bc0d8163f8ee84a8d5affdf624cfad657df1d2

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499.004Application or System Exploitation

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

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Your stack

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