In the Linux kernel, the following vulnerability has been resolved: mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk() In pcpu_create_chunk(), nr_pages is the total contiguous backing allocation, i.e., nr_units * pcpu_unit_pages, but pcpu_chunk_populated() uses it to set chunk->populated, whose size is pcpu_unit_pages, bitmap. Since bit N in chunk->populated means page offset N inside every unit is backed. When nr_units > 1, the function writes beyond chunk->populated. Fix it by using chunk->nr_pages. It also fixes the global pcpu_nr_empty_pop_pages accounting, since pcpu_balance_free() only iterates up to chunk->nr_pages. Commit a63d4ac4ab609 ("percpu: make percpu-km set chunk->populated bitmap properly") introduced the bitmap overflow issue. Later, commit b539b87fed37f ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated") added pcpu_nr_empty_pop_pages and caused the accounting issue.
History

Mon, 31 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-682

Mon, 31 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-805
References
Metrics threat_severity

None

threat_severity

Moderate


Sat, 29 Aug 2026 09:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-682

Sat, 29 Aug 2026 08:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119

Sat, 29 Aug 2026 06:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


Fri, 28 Aug 2026 17:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119

Fri, 28 Aug 2026 14:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119
CWE-787

Fri, 28 Aug 2026 11:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119
CWE-787

Fri, 28 Aug 2026 07:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk() In pcpu_create_chunk(), nr_pages is the total contiguous backing allocation, i.e., nr_units * pcpu_unit_pages, but pcpu_chunk_populated() uses it to set chunk->populated, whose size is pcpu_unit_pages, bitmap. Since bit N in chunk->populated means page offset N inside every unit is backed. When nr_units > 1, the function writes beyond chunk->populated. Fix it by using chunk->nr_pages. It also fixes the global pcpu_nr_empty_pop_pages accounting, since pcpu_balance_free() only iterates up to chunk->nr_pages. Commit a63d4ac4ab609 ("percpu: make percpu-km set chunk->populated bitmap properly") introduced the bitmap overflow issue. Later, commit b539b87fed37f ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated") added pcpu_nr_empty_pop_pages and caused the accounting issue.
Title mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-08-28T06:53:15.490Z

Updated: 2026-08-29T06:22:34.556Z

Reserved: 2026-08-26T14:34:25.788Z

Link: CVE-2026-80718

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-28T08:16:57.563

Modified: 2026-08-29T07:16:53.323

Link: CVE-2026-80718

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-28T00:00:00Z

Links: CVE-2026-80718 - Bugzilla