CVE-2026-45884 apparmor: avoid per-cpu hold underflow in aa_get_buffer

What is CVE-2026-45884?

CVE-2026-45884 is a medium-severity vulnerability in Linux kernel, published on 27 May 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: avoid per-cpu hold underflow in aa_get_buffer

When aa_get_buffer() pulls from the per-cpu list it unconditionally decrements cache->hold. If hold reaches 0 while count is still non-zero, the unsigned decrement wraps to UINT_MAX. This keeps hold non-zero for a very long time, so aa_put_buffer() never returns buffers to the global list, which can starve other CPUs and force repeated kmalloc(aa_g_path_max) allocations.

Guard the decrement so hold never underflows.

Weakness: CWE-191

Which versions are affected by CVE-2026-45884?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-45884?

Apply the vendor's patch.

Is CVE-2026-45884 being exploited?

There is no known exploitation of CVE-2026-45884 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 BELL-CVE-2026-45884, DEBIAN-CVE-2026-45884, GHSA-8h74-qh3g-94fx, ROOT-OS-UBUNTU-2404-CVE-2026-45884, UBUNTU-CVE-2026-45884.