CVE-2026-23408 apparmor: Fix double free of ns_name in aa_replace_profiles()

What is CVE-2026-23408?

CVE-2026-23408 is a high-severity use after free vulnerability in Linux kernel, published on 1 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

apparmor: Fix double free of ns_name in aa_replace_profiles()

if ns_name is NULL after 1071 error = aa_unpack(udata, &lh, &ns_name);

and if ent->ns_name contains an ns_name in 1089 } else if (ent->ns_name) {

then ns_name is assigned the ent->ns_name 1095 ns_name = ent->ns_name;

however ent->ns_name is freed at 1262 aa_load_ent_free(ent);

and then again when freeing ns_name at 1270 kfree(ns_name);

Fix this by NULLing out ent->ns_name after it is transferred to ns_name

")

Weakness: CWE-415

Which versions are affected by CVE-2026-23408?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23408?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-23408 being exploited?

There is no known exploitation of CVE-2026-23408 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-82028, BELL-CVE-2026-23408, DEBIAN-CVE-2026-23408, GHSA-qcx9-4fj7-jf29, UBUNTU-CVE-2026-23408.