VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90061: Linux kernel · netfilter: nf_tables: skip double clone set expressions on element insert

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in c6b56b8d549a043b6c8ff616db8748263eae05ae : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in c6b56b8d549a043b6c8ff616db8748263eae05ae, 43559058d21e0493aa220ac167e0279334dea5f9, 9cbf6da967ec8c6e8278b70353b712980a12d848 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 65038428b2c6c5be79d3f78a6b79c0cdc3a58a41, < c6b56b8d549a043b6c8ff616db8748263eae05ae	Fixed in c6b56b8d549a043b6c8ff616db8748263eae05ae
LinuxLinux	Affected ≥ 65038428b2c6c5be79d3f78a6b79c0cdc3a58a41, < 43559058d21e0493aa220ac167e0279334dea5f9	Fixed in 43559058d21e0493aa220ac167e0279334dea5f9
LinuxLinux	Affected ≥ 65038428b2c6c5be79d3f78a6b79c0cdc3a58a41, < 9cbf6da967ec8c6e8278b70353b712980a12d848	Fixed in 9cbf6da967ec8c6e8278b70353b712980a12d848
LinuxLinux	Affected ≥ 65038428b2c6c5be79d3f78a6b79c0cdc3a58a41, < 04d1930072e694d9d03bfefdb7e1ebdc872a3d0c	Fixed in 04d1930072e694d9d03bfefdb7e1ebdc872a3d0c
LinuxLinux	Affected ≥ 65038428b2c6c5be79d3f78a6b79c0cdc3a58a41, < 1e7fb6801d9cc826adcdb7fa0533c397730657f2	Fixed in 1e7fb6801d9cc826adcdb7fa0533c397730657f2
LinuxLinux	Affected =5.7	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: skip double clone set expressions on element insert Both the dynset and newsetelem path clone the existing set expressions when setting set element expressions if no override expressions are provided. This results in a double clone, once to clone the template set expressions then another clone on the new element. Add a flag to annotate if userspace provides a override expression (ie. expression of the same type of the set but different configuration), otherwise borrow the existing expression from the set. Add conditionals to release expression iif they represent an override. Use this new override_exprs flag to dump the dynset expression override to userspace. This simplifies the existing logic and it also fixes a bug with the connlimit expression which results in a module refcount imbalance WARNING splat when resorting on the default set expressions.

References

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