CVE-2026-74601

Local denial of service via ring-buffer swap race

Published Aug 22, 2026 · Updated Aug 25, 2026

Race condition in the Linux kernel ring buffer allows local users to crash the system by concurrently writing to and swapping per-CPU buffers. In ring_buffer_swap_cpu(), the committing counter temporarily reaches zero inside rb_move_tail(), so an interrupt can swap an in-use buffer before the writer completes. The path requires low-privileged tracefs writes, and successful exploitation can panic the host; Red Hat reports availability impact only.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Race condition in the Linux kernel ring buffer allows local users to crash the system by concurrently writing to and swapping per-CPU buffers. In ring_buffer_swap_cpu(), the committing counter temporarily reaches zero inside rb_move_tail(), so an interrupt can swap an in-use buffer before the writer completes. The path requires low-privileged tracefs writes, and successful exploitation can panic the host; Red Hat reports availability impact only.

The record

CVE
CVE-2026-74601
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-367, CWE-362, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <22709117d9ae95e52673685f98caac7c356a8227
  2. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <26662bc8fced1d668fa1aa146eda085bfc67bd0b
  3. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <597f279b7b4a06412e3d965e98cc36e181cdbede
  4. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f
  5. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <5e6e2a18c20e88167d414f666032792e8bf19b80
  6. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <6b524e6b234e45c7f5f90d13b042c6f57f80105c
  7. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <ad7e10c7ea89af45ac1bf1814855d45da472703d
  8. Affected versionversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <f27bdc43077e4fcb5557dfc315ee8d91e741f483
  9. Affected versionversion=4.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <22709117d9ae95e52673685f98caac7c356a8227; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <26662bc8fced1d668fa1aa146eda085bfc67bd0b; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <597f279b7b4a06412e3d965e98cc36e181cdbede; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <5e6e2a18c20e88167d414f666032792e8bf19b80; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <6b524e6b234e45c7f5f90d13b042c6f57f80105c; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <ad7e10c7ea89af45ac1bf1814855d45da472703d; version=4239c38fe0b3847e1e6d962c74b41b08ba0e2990 <f27bdc43077e4fcb5557dfc315ee8d91e741f483; version=4.5

Published CVSS scores

7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Red HatCVSS: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.

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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

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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

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Your stack

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