CVE-2026-72256

netfilter: xt_cluster: reject template conntracks in hash match

State: Published
Severity: Not scored
Published: Aug 15, 2026
Updated: Aug 17, 2026
Reserved: Aug 9, 2026

Description

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	0269ea4937343536ec7e85649932bc8c9686ea78 to before 4558bd7b47c7be82dffd837f27be8ea3ecee557dAffected 0269ea4937343536ec7e85649932bc8c9686ea78 to before d5f9d050b0b267227c1f02f11021872c7768a9ccAffected 0269ea4937343536ec7e85649932bc8c9686ea78 to before 4cb8b5f586e41c187942291cc0938006077fa79eAffected 0269ea4937343536ec7e85649932bc8c9686ea78 to before fac2fdac3baad9ffd12b3b0bba4374d4b3585d54Affected 0269ea4937343536ec7e85649932bc8c9686ea78 to before 13ea4f86cf738c74be2146886ac261988a631e62Affected 0269ea4937343536ec7e85649932bc8c9686ea78 to before 07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5Affected 0269ea4937343536ec7e85649932bc8c9686ea78 to before 5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aaAffected 0269ea4937343536ec7e85649932bc8c9686ea78 to before 5feba91006ec92da57acc1cc2e34df623b98541eAffected
LinuxLinux	2.6.30Affected before 2.6.30Not affected 5.10.261 through 5.10.Not affected 5.15.212 through 5.15.Not affected 6.1.178 through 6.1.Not affected 6.6.145 through 6.6.Not affected 6.12.97 through 6.12.Not affected 6.18.40 through 6.18.Not affected 7.1.5 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

0269ea4937343536ec7e85649932bc8c9686ea78 to before 4558bd7b47c7be82dffd837f27be8ea3ecee557dAffected
0269ea4937343536ec7e85649932bc8c9686ea78 to before d5f9d050b0b267227c1f02f11021872c7768a9ccAffected
0269ea4937343536ec7e85649932bc8c9686ea78 to before 4cb8b5f586e41c187942291cc0938006077fa79eAffected
0269ea4937343536ec7e85649932bc8c9686ea78 to before fac2fdac3baad9ffd12b3b0bba4374d4b3585d54Affected
0269ea4937343536ec7e85649932bc8c9686ea78 to before 13ea4f86cf738c74be2146886ac261988a631e62Affected
0269ea4937343536ec7e85649932bc8c9686ea78 to before 07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5Affected
0269ea4937343536ec7e85649932bc8c9686ea78 to before 5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aaAffected
0269ea4937343536ec7e85649932bc8c9686ea78 to before 5feba91006ec92da57acc1cc2e34df623b98541eAffected

LinuxLinux

2.6.30Affected
before 2.6.30Not affected
5.10.261 through 5.10.*Not affected
5.15.212 through 5.15.*Not affected
6.1.178 through 6.1.*Not affected
6.6.145 through 6.6.*Not affected
6.12.97 through 6.12.*Not affected
6.18.40 through 6.18.*Not affected
7.1.5 through 7.1.*Not affected
7.2 and laterNot affected

References

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