CVE-2026-74740

Kernel crash via traffic-control action race

Published Aug 26, 2026 · Updated Aug 26, 2026

A race in the Linux kernel traffic-control action path allows attackers to crash the kernel through concurrent action replacement. tcf_action_exec() checks a->goto_chain, but tcf_action_goto_chain_exec() reads it again and dereferences chain->filter_chain after a concurrent tcf_action_set_ctrlact() clears the pointer. Triggering requires TC_ACT_GOTO_CHAIN processing to overlap a control-action replacement; the resulting NULL dereference can terminate the system.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race in the Linux kernel traffic-control action path allows attackers to crash the kernel through concurrent action replacement. tcf_action_exec() checks a->goto_chain, but tcf_action_goto_chain_exec() reads it again and dereferences chain->filter_chain after a concurrent tcf_action_set_ctrlact() clears the pointer. Triggering requires TC_ACT_GOTO_CHAIN processing to overlap a control-action replacement; the resulting NULL dereference can terminate the system.

The record

CVE
CVE-2026-74740
Published
Aug 26, 2026
Updated
Aug 26, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 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=5.1
  2. Affected versionversion=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <1ec48b6715c29b20105e3485206602cff6c51ae5
  3. Affected versionversion=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <6b70886ebc428eed43a069c8944a931b5fb3f4e4
  4. Affected versionversion=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <91d55fd1fdb85c8371ca8793c788ea7d5192383a
  5. Affected versionversion=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <abceabc4408fca6a9dd52611f5d197dec9390d63
  6. Affected versionversion=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <f60b396ee174206fe08ebf997d16cd3801b77b22

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.1; version=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <1ec48b6715c29b20105e3485206602cff6c51ae5; version=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <6b70886ebc428eed43a069c8944a931b5fb3f4e4; version=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <91d55fd1fdb85c8371ca8793c788ea7d5192383a; version=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <abceabc4408fca6a9dd52611f5d197dec9390d63; version=ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 <f60b396ee174206fe08ebf997d16cd3801b77b22

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.

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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)
VectorUnavailable
PrivilegesUnavailable
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

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Your stack

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