CVE-2026-43201 APEI/GHES: ARM processor Error: don't go past allocated memory

Medium 5.5 Published 6 May 2026 Updated 23 May 2026

A missing bounds check in the Linux kernel's APEI/GHES ARM error handling allows a local attacker to cause a system crash via a malformed BIOS error record.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-43201?

CVE-2026-43201 is a medium-severity vulnerability in Linux kernel, published on 6 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:

APEI/GHES: ARM processor Error: don't go past allocated memory

If the BIOS generates a very small ARM Processor Error, or an incomplete one, the current logic will fail to deferrence

err->section_length and ctx_info->size

Add checks to avoid that. With such changes, such GHESv2 records won't cause OOPSes like this:

[ 1.492129] Internal error: Oops: 0000000096000005 [#1] SMP [ 1.495449] Modules linked in: [ 1.495820] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.18.0-rc1-00017-gabadcc3553dd-dirty #18 PREEMPT [ 1.496125] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 02/02/2022 [ 1.496433] Workqueue: kacpi_notify acpi_os_execute_deferred [ 1.496967] pstate: 814000c5 (Nzcv daIF +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 1.497199] pc : log_arm_hw_error+0x5c/0x200 [ 1.497380] lr : ghes_handle_arm_hw_error+0x94/0x220

0xffff8000811c5324 is in log_arm_hw_error (../drivers/ras/ras.c:75). 70 err_info = (struct cper_arm_err_info *)(err + 1); 71 ctx_info = (struct cper_arm_ctx_info *)(err_info + err->err_info_num); 72 ctx_err = (u8 *)ctx_info; 73 74 for (n = 0; n < err->context_info_num; n++) { 75 sz = sizeof(struct cper_arm_ctx_info) + ctx_info->size; 76 ctx_info = (struct cper_arm_ctx_info *)((long)ctx_info + sz); 77 ctx_len += sz; 78 } 79

and similar ones while trying to access section_length on an error dump with too small size.

[ rjw: Subject tweaks ]

Which versions are affected by CVE-2026-43201?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-43201?

Apply the vendor's patch.

Is CVE-2026-43201 being exploited?

There is no known exploitation of CVE-2026-43201 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-85886, BELL-CVE-2026-43201, DEBIAN-CVE-2026-43201, GHSA-2439-4xrr-7j2r, ROOT-OS-DEBIAN-11-CVE-2026-43201, ROOT-OS-DEBIAN-12-CVE-2026-43201 and 3 more.