Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_fw: fix NULL dereference of "old" filters before change() Like…
A vulnerability in the Linux kernel's cls_fw module caused a NULL pointer dereference due to improper handling of "old-style" filters before their change() function is called. This flaw could lead to kernel warnings and potential crashes when invalid filters classify packets before being validated. The issue was fixed by skipping old-style classification on shared blocks, preventing the NULL dereference and associated WARN_ON() triggers.
AI Analysis
Technical Summary
The Linux kernel vulnerability in the net/sched cls_fw component involves a NULL pointer dereference triggered by invalid "old-style" filters that classify packets before their ->change() function is invoked. This occurs because filters are added to a shared block and published to the datapath prematurely. The flaw leads to a kernel WARN_ON() and a NULL dereference on 'q->handle' when processing packets with certain marks. The fix involves skipping old-style classification on shared blocks to avoid dereferencing NULL pointers and prevent kernel warnings and crashes.
Potential Impact
The vulnerability can cause kernel warnings and NULL pointer dereferences, potentially leading to kernel crashes or instability when processing network packets with malformed filters. This impacts system reliability and could disrupt network operations on affected Linux kernel versions.
Mitigation Recommendations
A fix is available that addresses the NULL pointer dereference by skipping old-style classification on shared blocks. Users should apply the official kernel updates that include this patch to resolve the issue. Patch status is confirmed by the presence of fixed versions beyond the affected ones listed.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_fw: fix NULL dereference of "old" filters before change() Like…
Description
A vulnerability in the Linux kernel's cls_fw module caused a NULL pointer dereference due to improper handling of "old-style" filters before their change() function is called. This flaw could lead to kernel warnings and potential crashes when invalid filters classify packets before being validated. The issue was fixed by skipping old-style classification on shared blocks, preventing the NULL dereference and associated WARN_ON() triggers.
CVSS v4.0
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 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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=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resoluteRun on your own infrastructure? 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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability in the net/sched cls_fw component involves a NULL pointer dereference triggered by invalid "old-style" filters that classify packets before their ->change() function is invoked. This occurs because filters are added to a shared block and published to the datapath prematurely. The flaw leads to a kernel WARN_ON() and a NULL dereference on 'q->handle' when processing packets with certain marks. The fix involves skipping old-style classification on shared blocks to avoid dereferencing NULL pointers and prevent kernel warnings and crashes.
Potential Impact
The vulnerability can cause kernel warnings and NULL pointer dereferences, potentially leading to kernel crashes or instability when processing network packets with malformed filters. This impacts system reliability and could disrupt network operations on affected Linux kernel versions.
Mitigation Recommendations
A fix is available that addresses the NULL pointer dereference by skipping old-style classification on shared blocks. Users should apply the official kernel updates that include this patch to resolve the issue. Patch status is confirmed by the presence of fixed versions beyond the affected ones listed.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-53080
- Osv Schema Version
- 1.7.0
- Aliases
- []
- 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"]
- Database Specific Severity
- null
- Cvss Version
- 4.0
Threat ID: 6a5a013491ae9bcd3f801a1c
Added to database: 07/17/2026, 10:17:24 UTC
Last enriched: 07/30/2026, 21:37:22 UTC
Last updated: 07/31/2026, 19:24:46 UTC
Views: 1
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