CVE-2026-23274Public exploit

Kernel control-flow hijack via uninitialized timer reuse

Published Mar 20, 2026 · Updated Mar 20, 2026

Use-before-initialization in Linux Kernel allows local users to hijack kernel control flow through crafted netfilter IDLETIMER rules. Revision 0 idletimer_tg_checkentry() reuses a revision 1 ALARM label and calls mod_timer() on timer->timer even though that timer_list was never initialized. Exploitation requires local low-privilege access and control of the reused allocation; successful use can read protected data or crash the kernel.

CVSS severity7.8
High
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

Use-before-initialization in Linux Kernel allows local users to hijack kernel control flow through crafted netfilter IDLETIMER rules. Revision 0 idletimer_tg_checkentry() reuses a revision 1 ALARM label and calls mod_timer() on timer->timer even though that timer_list was never initialized. Exploitation requires local low-privilege access and control of the reused allocation; successful use can read protected data or crash the kernel.

The record

CVE
CVE-2026-23274
Published
Mar 20, 2026
Updated
Mar 20, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.7
  2. Affected versionversion=68983a354a655c35d3fb204489d383a2a051fda7 <329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf
  3. Affected versionversion=68983a354a655c35d3fb204489d383a2a051fda7 <f228b9ae2a7e84d1153616d8e71c4236cb1f1309
  4. Affected versionversion=68983a354a655c35d3fb204489d383a2a051fda7 <f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.7; version=68983a354a655c35d3fb204489d383a2a051fda7 <329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf; version=68983a354a655c35d3fb204489d383a2a051fda7 <f228b9ae2a7e84d1153616d8e71c4236cb1f1309; version=68983a354a655c35d3fb204489d383a2a051fda7 <f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1

Published CVSS scores

7.8Linux Kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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