Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: drop logically empty buckets in mtype_del mtype_del() counts… (CVE-2026-31418)
A vulnerability in the Linux kernel's netfilter ipset subsystem was resolved, where logically empty buckets were not properly dropped in the mtype_del function. This flaw could cause issues related to resource management in the kernel. The vulnerability has been assigned CVE-2026-31418 and is rated medium severity with a CVSS score of 5.5. A patch is available and included in updated Linux kernel packages. Users should update and reboot their systems to apply the fix.
AI Analysis
Technical Summary
CVE-2026-31418 addresses a flaw in the Linux kernel netfilter ipset subsystem where the mtype_del() function incorrectly handles logically empty buckets. Specifically, it only drops a bucket when both n->pos and k are zero, missing buckets whose live entries have been removed but n->pos still points past deleted slots. The fix treats a bucket as empty when all positions below n->pos are unused and releases it directly instead of shrinking it further. This vulnerability affects multiple versions of the linux-hwe-edge kernel prior to specific patched versions. The issue was resolved in updated kernel releases as part of a broader set of Linux kernel security fixes.
Potential Impact
The vulnerability does not impact confidentiality or integrity but has an impact on availability (CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). An attacker with local privileges could potentially exploit this flaw to cause denial of service or resource exhaustion by manipulating ipset buckets. There are no known exploits in the wild. The medium severity rating reflects the limited attack vector (local access required) and the impact confined to availability.
Mitigation Recommendations
A patch is available and has been released by Ubuntu as part of their Linux kernel updates. Users should update their Linux kernel packages to the fixed versions listed in the Ubuntu advisories USN-8490-1 and USN-8491-1 and reboot their systems to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. No additional mitigation actions are necessary beyond applying the official updates.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: drop logically empty buckets in mtype_del mtype_del() counts… (CVE-2026-31418)
Description
A vulnerability in the Linux kernel's netfilter ipset subsystem was resolved, where logically empty buckets were not properly dropped in the mtype_del function. This flaw could cause issues related to resource management in the kernel. The vulnerability has been assigned CVE-2026-31418 and is rated medium severity with a CVSS score of 5.5. A patch is available and included in updated Linux kernel packages. Users should update and reboot their systems to apply the fix.
CVSS v3.1
Score 5.5medium
Affected software
pkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.2?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]+cvm1.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.3?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email 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protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-31418 addresses a flaw in the Linux kernel netfilter ipset subsystem where the mtype_del() function incorrectly handles logically empty buckets. Specifically, it only drops a bucket when both n->pos and k are zero, missing buckets whose live entries have been removed but n->pos still points past deleted slots. The fix treats a bucket as empty when all positions below n->pos are unused and releases it directly instead of shrinking it further. This vulnerability affects multiple versions of the linux-hwe-edge kernel prior to specific patched versions. The issue was resolved in updated kernel releases as part of a broader set of Linux kernel security fixes.
Potential Impact
The vulnerability does not impact confidentiality or integrity but has an impact on availability (CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). An attacker with local privileges could potentially exploit this flaw to cause denial of service or resource exhaustion by manipulating ipset buckets. There are no known exploits in the wild. The medium severity rating reflects the limited attack vector (local access required) and the impact confined to availability.
Mitigation Recommendations
A patch is available and has been released by Ubuntu as part of their Linux kernel updates. Users should update their Linux kernel packages to the fixed versions listed in the Ubuntu advisories USN-8490-1 and USN-8491-1 and reboot their systems to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. No additional mitigation actions are necessary beyond applying the official updates.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-31418
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:20.04:LTS","Ubuntu:Pro:FIPS-updates:20.04:LTS","Ubuntu:Pro:FIPS:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:Nvidia-BlueField:22.04:LTS","Ubuntu:Pro:FIPS-preview:22.04:LTS","Ubuntu:Pro:FIPS-updates:22.04:LTS","Ubuntu:Pro:Realtime:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:Nvidia-BlueField:24.04:LTS","Ubuntu:Pro:FIPS-updates:24.04:LTS","Ubuntu:Pro:Realtime:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6a58b4d768715ace43dabb43
Added to database: 07/16/2026, 10:39:19 UTC
Last enriched: 08/01/2026, 05:56:21 UTC
Last updated: 09/14/2026, 10:01:30 UTC
Views: 25
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