CVE-2026-43169 drm/buddy: Prevent BUG_ON by validating rounded allocation

What is CVE-2026-43169?

CVE-2026-43169 is a medium-severity denial of service 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:

drm/buddy: Prevent BUG_ON by validating rounded allocation

When DRM_BUDDY_CONTIGUOUS_ALLOCATION is set, the requested size is rounded up to the next power-of-two via roundup_pow_of_two(). Similarly, for non-contiguous allocations with large min_block_size, the size is aligned up via round_up(). Both operations can produce a rounded size that exceeds mm->size, which later triggers BUG_ON(order > mm->max_order).

Example scenarios: - 9G CONTIGUOUS allocation on 10G VRAM memory: roundup_pow_of_two(9G) = 16G > 10G - 9G allocation with 8G min_block_size on 10G VRAM memory: round_up(9G, 8G) = 16G > 10G

Fix this by checking the rounded size against mm->size. For non-contiguous or range allocations where size > mm->size is invalid, return -EINVAL immediately. For contiguous allocations without range restrictions, allow the request to fall through to the existing __alloc_contig_try_harder() fallback.

This ensures invalid user input returns an error or uses the fallback path instead of hitting BUG_ON.

v2: (Matt A) - Add Fixes, Cc stable, and Closes tags for context

Which versions are affected by CVE-2026-43169?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-43169?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-43169 being exploited?

There is no known exploitation of CVE-2026-43169 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-2026-43169, DEBIAN-CVE-2026-43169, GHSA-vpc5-6pmj-q288, ROOT-OS-UBUNTU-2404-CVE-2026-43169, UBUNTU-CVE-2026-43169.