CVE-2026-74593

System hang via reversed sched_ext lock order

Published Aug 22, 2026 · Updated Aug 22, 2026

Deadlock in Linux sched_ext 6.18 through 7.1.8 allows local users to hang the system through concurrent cgroup operations. scx_cgroup_lock() acquires scx_cgroup_ops_rwsem before cgroup_lock(), creating a cycle through kernfs_drain() when sched_ext toggling or cgroup removal overlaps a cpu.weight write. Low-privileged local access and precise concurrency are required; successful exploitation blocks kernel work system-wide without reported data access or modification.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in Linux sched_ext 6.18 through 7.1.8 allows local users to hang the system through concurrent cgroup operations. scx_cgroup_lock() acquires scx_cgroup_ops_rwsem before cgroup_lock(), creating a cycle through kernfs_drain() when sched_ext toggling or cgroup removal overlaps a cpu.weight write. Low-privileged local access and precise concurrency are required; successful exploitation blocks kernel work system-wide without reported data access or modification.

The record

CVE
CVE-2026-74593
Published
Aug 22, 2026
Updated
Aug 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-833, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 22, 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=6.18
  2. Affected versionversion=a5bd6ba30b3364354269b81ac55c2edca9a96d6d <5f8b69642d18e1f3e11996707842ac530444e959
  3. Affected versionversion=a5bd6ba30b3364354269b81ac55c2edca9a96d6d <a054c9ffa9b7a0dffb763837b91ac9d381ec6d10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.18; version=a5bd6ba30b3364354269b81ac55c2edca9a96d6d <5f8b69642d18e1f3e11996707842ac530444e959; version=a5bd6ba30b3364354269b81ac55c2edca9a96d6d <a054c9ffa9b7a0dffb763837b91ac9d381ec6d10

Published CVSS scores

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.

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

CWE-833Deadlock
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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