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NVD / CVE Program· CNA Linux

CVE-2026-72256: netfilter: xt_cluster: reject template conntracks in hash match

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5, 13ea4f86cf738c74be2146886ac261988a631e62, 4558bd7b47c7be82dffd837f27be8ea3ecee557d.

Low priority for now. Upgrade to Linux Linux 07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5, 13ea4f86cf738c74be2146886ac261988a631e62, 4558bd7b47c7be82dffd837f27be8ea3ecee557d or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_cluster: reject template conntracks in hash match xt_cluster_mt() treats any non-NULL nf_ct_get() result as a fully initialized conntrack and passes it to xt_cluster_hash(). This causes a state confusion bug when the raw table CT target attaches a template conntrack to skb->_nfct before normal conntrack processing. Templates carry IPS_TEMPLATE status but do not have a valid tuple for hashing yet, so xt_cluster_hash() can hit its WARN_ON() path on the zeroed l3num field. Reject template conntracks before hashing them. This matches existing netfilter handling for template objects and avoids hashing incomplete conntrack state.

—No exploit Fix available
Published
Aug 15, 2026
Updated
Nov 6, 2026
EPSS
0.2% · 12th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.30affected
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before 4558bd7b47c7be82dffd837f27be8ea3ecee557daffected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before d5f9d050b0b267227c1f02f11021872c7768a9ccaffected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before 4cb8b5f586e41c187942291cc0938006077fa79eaffected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before fac2fdac3baad9ffd12b3b0bba4374d4b3585d54affected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before 13ea4f86cf738c74be2146886ac261988a631e62affected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before 07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5affected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before 5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aaaffected · git
    • 0269ea4937343536ec7e85649932bc8c9686ea78 and later · before 5feba91006ec92da57acc1cc2e34df623b98541eaffected · git
    • before 2.6.30not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.180-16.1.180-1
Debian:13linuxbefore 6.12.100-16.12.100-1
Debian:14linuxbefore 7.1.5-17.1.5-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-72254Aug 15, 2026 · netfilter: nft_fib: reject fib expression on the netdev egress hook
    30Monitor
  • ← EarlierCVE-2026-72255Aug 15, 2026 · netfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst
    31Monitor
  • Later →CVE-2026-72261Aug 15, 2026 · ASoC: SOF: ipc3-control: Validate size in snd_sof_update_control
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5Vendor (CNA)
Linux Linux13ea4f86cf738c74be2146886ac261988a631e62Vendor (CNA)
Linux Linux4558bd7b47c7be82dffd837f27be8ea3ecee557dVendor (CNA)
Linux Linux4cb8b5f586e41c187942291cc0938006077fa79eVendor (CNA)
Linux Linux5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aaVendor (CNA)
Linux Linux5feba91006ec92da57acc1cc2e34df623b98541eVendor (CNA)
Linux Linuxd5f9d050b0b267227c1f02f11021872c7768a9ccVendor (CNA)
Linux Linuxfac2fdac3baad9ffd12b3b0bba4374d4b3585d54Vendor (CNA)
debian:linux6.1.180-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records