CVE-2026-72423

Kernel memory corruption via undersized conntrack options

Published Aug 15, 2026 · Updated Aug 15, 2026

Out-of-bounds write in affected Linux kernel builds allows local users to corrupt kernel memory through BPF conntrack kfunc calls. The lookup and allocation wrappers write opts->error after helper failures even when opts__sz covers less memory than that field, exceeding the verifier-checked range. Reachability requires local access and permission to load an invoking BPF program; resulting corruption can crash the system, while code execution has not been demonstrated.

CVSS severity8.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in affected Linux kernel builds allows local users to corrupt kernel memory through BPF conntrack kfunc calls. The lookup and allocation wrappers write opts->error after helper failures even when opts__sz covers less memory than that field, exceeding the verifier-checked range. Reachability requires local access and permission to load an invoking BPF program; resulting corruption can crash the system, while code execution has not been demonstrated.

The record

CVE
CVE-2026-72423
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=5.18
  2. Affected versionversion=b4c2b9593a1c4c3a718370e34af28e817fd5e5c6 <6f6183a39533d727deaa5061cadae6dd9e6744d0
  3. Affected versionversion=b4c2b9593a1c4c3a718370e34af28e817fd5e5c6 <dd74c80203842a21b2ebb9f70d1260d9aa20fa05

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.18; version=b4c2b9593a1c4c3a718370e34af28e817fd5e5c6 <6f6183a39533d727deaa5061cadae6dd9e6744d0; version=b4c2b9593a1c4c3a718370e34af28e817fd5e5c6 <dd74c80203842a21b2ebb9f70d1260d9aa20fa05

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
8.8CVE.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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.

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-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

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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