CVE-2026-80718: Linux Vulnerability (CVSS 7.8)

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.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.16%

5.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 5f43d2c1bea280dcdfabaf156c25e7402fb8039f; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 92c43ac3c2b09eb16162e8144e73c00b7c3e29d6; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 6fc7da2a052f2825fff785e860e67183f5acaaba; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 01504da375f5b19df195cb1cb1cf1dd184318f97; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < a6940b84c8c035da465b7165fdfcfb005545724e; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 32134cf9211b83bed9076d0739c5906fbea4c763; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 5c7fc39bf19abb38a996aaad77b3e3a8f48581c3; >= a63d4ac4ab6094c051a5a240260d16117a7a2f86, < 89b1b79c308818a715e75f28744b70d8940a07c9
Linux	Linux	3.18

References

Timeline

Published: Aug 28, 2026
Last Modified: Aug 29, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-80718?

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.

How severe is CVE-2026-80718?

CVE-2026-80718 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2026-80718?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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