High

CVE-2026-80718 — mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()

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.

Published Aug 28, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Linux

CVSS base

7.8

High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 5f43d2c1bea280dcdfabaf156c25e7402fb8039f≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 92c43ac3c2b09eb16162e8144e73c00b7c3e29d6≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 6fc7da2a052f2825fff785e860e67183f5acaaba≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 01504da375f5b19df195cb1cb1cf1dd184318f97≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < a6940b84c8c035da465b7165fdfcfb005545724e≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 32134cf9211b83bed9076d0739c5906fbea4c763≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 5c7fc39bf19abb38a996aaad77b3e3a8f48581c3≥ a63d4ac4ab6094c051a5a240260d16117a7a2f86 and < 89b1b79c308818a715e75f28744b70d8940a07c9 and 1 more version 3.18	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.8	CVSS 3.1	High	1.8	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 7.8
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 28, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

git.kernel.org/stable/c/89b1b79c308818a715e75f28744b70d8940a07c9
NIST National Vulnerability Database
git.kernel.org/stable/c/5f43d2c1bea280dcdfabaf156c25e7402fb8039f
NIST National Vulnerability Database
git.kernel.org/stable/c/92c43ac3c2b09eb16162e8144e73c00b7c3e29d6
NIST National Vulnerability Database
git.kernel.org/stable/c/5c7fc39bf19abb38a996aaad77b3e3a8f48581c3
NIST National Vulnerability Database
git.kernel.org/stable/c/6fc7da2a052f2825fff785e860e67183f5acaaba
NIST National Vulnerability Database
git.kernel.org/stable/c/01504da375f5b19df195cb1cb1cf1dd184318f97
NIST National Vulnerability Database
git.kernel.org/stable/c/a6940b84c8c035da465b7165fdfcfb005545724e
NIST National Vulnerability Database
git.kernel.org/stable/c/32134cf9211b83bed9076d0739c5906fbea4c763
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 11h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 11h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-80718 is "mm/percpu-km: fix bitmap overflow and accounting in pcpu_create_chunk()", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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