CVE-2026-80718

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.

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EPSS — Exploit Prediction

0.0016

Probability of exploitation

0.06%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/01504da375f5b19df195cb1cb1cf1dd184318f97 https://git.kernel.org/stable/c/32134cf9211b83bed9076d0739c5906fbea4c763 https://git.kernel.org/stable/c/5c7fc39bf19abb38a996aaad77b3e3a8f48581c3 https://git.kernel.org/stable/c/5f43d2c1bea280dcdfabaf156c25e7402fb8039f https://git.kernel.org/stable/c/6fc7da2a052f2825fff785e860e67183f5acaaba https://git.kernel.org/stable/c/89b1b79c308818a715e75f28744b70d8940a07c9 https://git.kernel.org/stable/c/92c43ac3c2b09eb16162e8144e73c00b7c3e29d6 https://git.kernel.org/stable/c/a6940b84c8c035da465b7165fdfcfb005545724e

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 do I check if I'm vulnerable to CVE-2026-80718? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.