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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 5.5, 5.6, 58f3a14826d4e6b0d5421f1a64be280b48601ea2; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2.

Low priority for now. Upgrade to Linux Linux 5.5, 5.6, 58f3a14826d4e6b0d5421f1a64be280b48601ea2; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2 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: 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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Apr 13, 2026
Updated
Nov 5, 2026
EPSS
0.1% · 1th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-31418

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.4.24 and later · before 5.5
  • linux linux kernel5.5.8 and later · before 5.6
  • linux linux kernel5.6.1 and later · before 5.10.253
  • linux linux kernel5.11 and later · before 5.15.203
  • linux linux kernel5.16 and later · before 6.1.168
  • linux linux kernel6.2 and later · before 6.6.134
  • linux linux kernel6.7 and later · before 6.12.81
  • linux linux kernel6.13 and later · before 6.18.22
  • linux linux kernel6.19 and later · before 6.19.12
  • linux linux kernel5.6
  • linux linux kernel7.0

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

    • 6c717726f341fd8f39a3ec2dcf5d98d9d28a2769, d2997d64dfa65082236bca1efd596b6c935daf5e, 5.6affected
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before c098ff857e7ca923539164af5b3c2fe3e8f8afafaffected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before 58f3a14826d4e6b0d5421f1a64be280b48601ea2affected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before ad92ee87462f9a3061361d392e9dbfe2e5c1c9fbaffected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before 6cea34d7ec6829b62f521a37a287f670144a2233affected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before b7eef00f08b92b0b9efe8ae0df6d0005e6199323affected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before 68ca0eea0af02bed36c5e2c13e9fa1647c31a7d4affected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before ceacaa76f221a6577aba945bb8873c2e640aeba4affected · git
    • 8af1c6fbd9239877998c7f5a591cb2c88d41fb66 and later · before 9862ef9ab0a116c6dca98842aab7de13a252ae02affected · git
    • 5.4.24 and later · before 5.5affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.12-16.19.12-1
openSUSE:Leap 16.0dtb-aarch64before 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-64kbbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-azurebefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-defaultbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-default-basebefore 6.12.0-160000.38.1.160000.2.226.12.0-160000.38.1.160000.2.22
openSUSE:Leap 16.0kernel-docsbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-kvmsmallbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-obs-buildbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-obs-qabefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-rtbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-sourcebefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-symsbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-zfcpdumpbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_21before 1-150700.15.3.11-150700.15.3.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7-RT_Update_20before 1-150700.1.3.11-150700.1.3.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-64kbbefore 6.4.0-150700.53.81.16.4.0-150700.53.81.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-defaultbefore 6.4.0-150700.53.81.16.4.0-150700.53.81.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-default-basebefore 6.4.0-150700.53.81.1.150700.17.45.16.4.0-150700.53.81.1.150700.17.45.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-sourcebefore 6.4.0-150700.53.81.16.4.0-150700.53.81.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7kernel-zfcpdumpbefore 6.4.0-150700.53.81.16.4.0-150700.53.81.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7kernel-docsbefore 6.4.0-150700.53.81.16.4.0-150700.53.81.1

+25

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-31416Apr 13, 2026 · netfilter: nfnetlink_log: account for netlink header size
    22Monitor
  • ← EarlierCVE-2026-31417Apr 13, 2026 · net/x25: Fix overflow when accumulating packets
    30Monitor
  • Later →CVE-2026-31419Apr 13, 2026 · net: bonding: fix use-after-free in bond_xmit_broadcast()
    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 Linux5.5Vendor (CNA)
Linux Linux5.6Vendor (CNA)
Linux Linux58f3a14826d4e6b0d5421f1a64be280b48601ea2Vendor (CNA)
Linux Linux68ca0eea0af02bed36c5e2c13e9fa1647c31a7d4Vendor (CNA)
Linux Linux6cea34d7ec6829b62f521a37a287f670144a2233Vendor (CNA)
Linux Linux9862ef9ab0a116c6dca98842aab7de13a252ae02Vendor (CNA)
Linux Linuxad92ee87462f9a3061361d392e9dbfe2e5c1c9fbVendor (CNA)
Linux Linuxb7eef00f08b92b0b9efe8ae0df6d0005e6199323Vendor (CNA)
Linux Linuxc098ff857e7ca923539164af5b3c2fe3e8f8afafVendor (CNA)
Linux Linuxceacaa76f221a6577aba945bb8873c2e640aeba4Vendor (CNA)
azl3 kernel 6.6.130.1-3 on Azure Linux 3.06.6.134.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
opensuse:dtb-aarch646.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-64kb6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-azure6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default-base6.12.0-160000.38.1.160000.2.22 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-docs6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-kvmsmall6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-build6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-qa6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-rt6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-source6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-syms6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
suse:kernel-64kb6.12.0-160000.38.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-64kb6.4.0-150700.53.81.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:kernel-azure6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-default6.4.0-52.1 · SUSE:Linux Micro 6.0Package registry (OSV)
suse:kernel-default-base6.4.0-52.1.21.36 · SUSE:Linux Micro 6.0Package registry (OSV)
suse:kernel-docs6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

+12

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.

No history yet (it accumulates with the daily EPSS job).

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

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 (10 more)

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

All records