🛡️ UBUNTU-CVE-2026-31421
⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_fw: fix NULL pointer dereference on shared blocks The old-method path in fw_classify() calls tcf_block_q() and dereferences q->handle. Shared blocks leave block->q NULL, causing a NULL deref when an empty cls_fw filter is attached to a shared block and a packet with a nonzero major skb mark is classified. Reject the configuration in fw_change() when the old method (no TCA_OPTIONS) is used on a shared block, since fw_classify()'s old-method path needs block->q which is NULL for shared blocks. The fixed null-ptr-deref calling stack: KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f] RIP: 0010:fw_classify (net/sched/cls_fw.c:81) Call Trace: tcf_classify (./include/net/tc_wrapper.h:197 net/sched/cls_api.c:1764 net/sched/cls_api.c:1860) tc_run (net/core/dev.c:4401) __dev_queue_xmit (net/core/dev.c:4535 net/core/dev.c:4790)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-04-13
Updated 2026-06-15
Modified 2026-06-08
Fix URL N/A

Affected Packages

Software From version Fixed in
linux
linux-allwinner-5.19
linux-aws
linux-aws-5.0
linux-aws-5.11
linux-aws-5.13
linux-aws-5.15
linux-aws-5.19
linux-aws-5.3
linux-aws-5.4
linux-aws-5.8
linux-aws-6.14
linux-aws-6.17
linux-aws-6.2
linux-aws-6.5
linux-aws-6.8
linux-aws-fips
linux-aws-hwe
linux-azure
linux-azure-4.15
linux-azure-5.11
linux-azure-5.13
linux-azure-5.15
linux-azure-5.19
linux-azure-5.3
linux-azure-5.4
linux-azure-5.8
linux-azure-6.11
linux-azure-6.14
linux-azure-6.17
linux-azure-6.2
linux-azure-6.5
linux-azure-6.8
linux-azure-edge
linux-azure-fde
linux-azure-fde-5.19
linux-azure-fde-6.14
linux-azure-fde-6.17
linux-azure-fde-6.2
linux-azure-fde-6.8
linux-azure-fips
linux-azure-nvidia
linux-azure-nvidia-6.14
linux-bluefield
linux-fips
linux-gcp
linux-gcp-4.15
linux-gcp-5.11
linux-gcp-5.13
linux-gcp-5.15
linux-gcp-5.19
linux-gcp-5.3
linux-gcp-5.4
linux-gcp-5.8
linux-gcp-6.11
linux-gcp-6.14
linux-gcp-6.17
linux-gcp-6.2
linux-gcp-6.5
linux-gcp-6.8
linux-gcp-fips
linux-gke
linux-gke-4.15
linux-gke-5.15
linux-gke-5.4
linux-gkeop
linux-gkeop-5.15
linux-gkeop-5.4
linux-hwe
linux-hwe-5.11
linux-hwe-5.13
linux-hwe-5.15
linux-hwe-5.19
linux-hwe-5.4
linux-hwe-5.8
linux-hwe-6.11
linux-hwe-6.14
linux-hwe-6.17
linux-hwe-6.2
linux-hwe-6.5
linux-hwe-6.8
linux-hwe-edge
linux-ibm
linux-ibm-5.15
linux-ibm-5.4
linux-ibm-6.8
linux-intel-5.13
linux-intel-iot-realtime
linux-intel-iotg
linux-intel-iotg-5.15
linux-iot
linux-kvm
linux-lowlatency
linux-lowlatency-hwe-5.15
linux-lowlatency-hwe-5.19
linux-lowlatency-hwe-6.11
linux-lowlatency-hwe-6.2
linux-lowlatency-hwe-6.5
linux-lowlatency-hwe-6.8
linux-nvidia 7.0.0-1006.6
linux-nvidia-6.11
linux-nvidia-6.17
linux-nvidia-6.2
linux-nvidia-6.5
linux-nvidia-6.8
linux-nvidia-lowlatency
linux-nvidia-tegra
linux-nvidia-tegra-5.15
linux-nvidia-tegra-igx
linux-oem
linux-oem-5.10
linux-oem-5.13
linux-oem-5.14
linux-oem-5.17
linux-oem-5.6
linux-oem-6.0
linux-oem-6.1
linux-oem-6.11
linux-oem-6.14
linux-oem-6.17
linux-oem-6.5
linux-oem-6.8
linux-oracle
linux-oracle-5.0
linux-oracle-5.11
linux-oracle-5.13
linux-oracle-5.15
linux-oracle-5.3
linux-oracle-5.4
linux-oracle-5.8
linux-oracle-6.14
linux-oracle-6.17
linux-oracle-6.5
linux-oracle-6.8
linux-raspi
linux-raspi-5.4
linux-raspi-realtime
linux-raspi2
linux-realtime
linux-realtime-6.14
linux-realtime-6.17
linux-realtime-6.8
linux-riscv
linux-riscv-5.11
linux-riscv-5.15
linux-riscv-5.19
linux-riscv-5.8
linux-riscv-6.14
linux-riscv-6.17
linux-riscv-6.5
linux-riscv-6.8
linux-starfive-5.19
linux-starfive-6.2
linux-starfive-6.5
linux-xilinx
linux-xilinx-zynqmp

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