VulnerabilityPublished 13 Apr 2026Updated 5 Nov 2026

CVE-2026-31418: Linux kernel · netfilter: ipset: drop logically empty buckets in mtype_del

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in ceacaa76f221a6577aba945bb8873c2e640aeba4 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 22:04 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in ceacaa76f221a6577aba945bb8873c2e640aeba4, c098ff857e7ca923539164af5b3c2fe3e8f8afaf, b7eef00f08b92b0b9efe8ae0df6d0005e6199323 +7

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 5 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 >=5.4.24 <5.5 >=5.5.8 <5.6	Fixed in ceacaa76f221a6577aba945bb8873c2e640aeba4 c098ff857e7ca923539164af5b3c2fe3e8f8afaf b7eef00f08b92b0b9efe8ae0df6d0005e6199323 ad92ee87462f9a3061361d392e9dbfe2e5c1c9fb 9862ef9ab0a116c6dca98842aab7de13a252ae02 68ca0eea0af02bed36c5e2c13e9fa1647c31a7d4 58f3a14826d4e6b0d5421f1a64be280b48601ea2 6cea34d7ec6829b62f521a37a287f670144a2233 5.6 5.5
LinuxLinux	Affected =5.6	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: drop logically empty buckets in mtype_del mtype_del() counts empty slots below n->pos in k, but it only drops the bucket when both n->pos and k are zero. This misses buckets whose live entries have all been removed while n->pos still points past deleted slots. Treat a bucket as empty when all positions below n->pos are unused and release it directly instead of shrinking it further.

References

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