Use-after-free in Linux kernel - CVE-2026-23226

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Main Vulnerability Database Vulnerabilities #VU123033

Use-after-free in Linux kernel - CVE-2026-23226

Published: February 18, 2026


Vulnerability identifier: #VU123033
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-23226
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the check_session_id(), ntlm_authenticate() and krb5_authenticate() functions in fs/smb/server/smb2pdu.c. A local user can escalate privileges on the system.


Affected software

Linux kernel
Debian Linux
Ubuntu
openEuler
python3-perf-debuginfo
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-headers
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
python3-perf
kernel-source
kernel-extra-modules
linux (Ubuntu package)
linux-fips (Ubuntu package)
linux-hwe-6.8 (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-fde (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux (Debian package)

How to mitigate CVE-2026-23226

Install update from vendor's repository.

python3-perf-debuginfo - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
bpftool - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
bpftool-debuginfo - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-debuginfo - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-debugsource - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-devel - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-headers - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-tools - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-tools-debuginfo - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-tools-devel - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
perf - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
perf-debuginfo - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
python3-perf - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-source - addressed in versions 6.6.0-143.0.0.125, 6.6.0-143.0.0.137, 6.6.0-143.0.0.138
kernel-extra-modules - update to 6.6.0-143.0.0.138
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-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
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-fde (Ubuntu package) - update to 6.8.0-1062.69
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1063.71, 6.8.0-1063.71~22.04.1
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
linux (Debian package) - update to 6.12.85-1

External References

Related Security Bulletins