Use-after-free in Linux kernel - CVE-2026-43084

Vulnerability identifier: #VU130677

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-43084

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in nfnetlink_queue when processing queue verdicts in parallel. A local user can send crafted netfilter queue verdict messages to trigger a kernel crash.

The issue occurs because an nf_queue_entry may be freed on one CPU while still being encountered by another CPU walking the shared list.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-fips (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72, 6.8.0-1064.72~22.04.1, 6.8.1-1056.57, 6.8.1-1056.57~22.04.2
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2, 6.8.0-136.136.2~22.04.1, 6.8.0-1058.61
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62, 6.8.0-1061.62~22.04.1
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62, 6.8.0-1059.62.1, 6.8.0-1059.62~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64+fips1, 6.8.0-1061.64~22.04.1
linux-aws (Ubuntu package) - update to 6.8.0-1061.64+1
linux-azure-fips (Ubuntu package) - update to 6.8.0-1063.71+fips2
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1

• https://git.kernel.org/stable/c/22730cb96093b5be0609063bbb1923dbecd61252
• https://git.kernel.org/stable/c/41e3652a178cb0eecd48e0e6e27fbb73a004046a
• https://git.kernel.org/stable/c/936206e3f6ff411581e615e930263d6f8b78df9d
• https://git.kernel.org/stable/c/9e5ebef91120d2764aefe557c3a484b6288f341f

• Use-after-free in Linux kernel netfilter
• Ubuntu update for linux
• Ubuntu update for linux-gcp-fips
• Ubuntu update for linux-oracle-6.8
• Ubuntu update for linux-fips
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-azure-fips
• Ubuntu update for linux-aws
• Ubuntu update for linux-aws-6.8
• Ubuntu update for linux-ibm