CVE-2026-72256

Service interruption via incomplete conntrack hashing

Published Aug 15, 2026 · Updated Aug 15, 2026

State confusion in Linux netfilter allows local users to cause a service interrupt by forcing a template conntrack into xt_cluster hashing. xt_cluster_mt passes every non-null nf_ct_get result to xt_cluster_hash without rejecting IPS_TEMPLATE objects, whose tuple is not initialized. Reaching the WARN_ON path requires the raw-table CT target to attach a template before normal connection tracking; a crash depends on warning-panic policy.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

State confusion in Linux netfilter allows local users to cause a service interrupt by forcing a template conntrack into xt_cluster hashing. xt_cluster_mt passes every non-null nf_ct_get result to xt_cluster_hash without rejecting IPS_TEMPLATE objects, whose tuple is not initialized. Reaching the WARN_ON path requires the raw-table CT target to attach a template before normal connection tracking; a crash depends on warning-panic policy.

The record

CVE
CVE-2026-72256
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
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

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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=0269ea4937343536ec7e85649932bc8c9686ea78 <07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5
  2. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <13ea4f86cf738c74be2146886ac261988a631e62
  3. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <4558bd7b47c7be82dffd837f27be8ea3ecee557d
  4. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <4cb8b5f586e41c187942291cc0938006077fa79e
  5. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aa
  6. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <5feba91006ec92da57acc1cc2e34df623b98541e
  7. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <d5f9d050b0b267227c1f02f11021872c7768a9cc
  8. Affected versionversion=0269ea4937343536ec7e85649932bc8c9686ea78 <fac2fdac3baad9ffd12b3b0bba4374d4b3585d54
  9. Affected versionversion=2.6.30

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0269ea4937343536ec7e85649932bc8c9686ea78 <07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5; version=0269ea4937343536ec7e85649932bc8c9686ea78 <13ea4f86cf738c74be2146886ac261988a631e62; version=0269ea4937343536ec7e85649932bc8c9686ea78 <4558bd7b47c7be82dffd837f27be8ea3ecee557d; version=0269ea4937343536ec7e85649932bc8c9686ea78 <4cb8b5f586e41c187942291cc0938006077fa79e; version=0269ea4937343536ec7e85649932bc8c9686ea78 <5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aa; version=0269ea4937343536ec7e85649932bc8c9686ea78 <5feba91006ec92da57acc1cc2e34df623b98541e; version=0269ea4937343536ec7e85649932bc8c9686ea78 <d5f9d050b0b267227c1f02f11021872c7768a9cc; version=0269ea4937343536ec7e85649932bc8c9686ea78 <fac2fdac3baad9ffd12b3b0bba4374d4b3585d54; version=2.6.30

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
5.5Oracle LinuxCVSS: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

T1499.004Application or System Exploitation

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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