CVE-2026-43169

drm/buddy: Prevent BUG_ON by validating rounded allocation

Published May 6, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
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

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8492-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8492-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8497-1 Linux kernel (Low Latency) vulnerabilities
Ubuntu USN Ubuntu USN USN-8498-1 Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN Ubuntu USN USN-8499-1 Linux kernel (Xilinx) vulnerabilities
Ubuntu USN Ubuntu USN USN-8492-3 Linux kernel (Raspberry Pi Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8492-4 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8492-5 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8606-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8607-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8609-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8619-1 Linux kernel (HWE) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
Weaknesses CWE-131
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
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
Title drm/buddy: Prevent BUG_ON by validating rounded allocation
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Nov 6, 2026, 3:32 PM
Reserved
May 1, 2026, 2:12 PM
Status
Analyzed
Published
May 6, 2026, 12:16 PM
Modified
Nov 11, 2026, 8:10 PM
Severity
Moderate
Public date
May 6, 2026, 12:00 AM