NVD / CVE Program· CNA Linux

CVE-2026-97526: s390/pai: Support CPU hotplug for PMU PAI

Noroxi assessment

Priority: Monitor (action score 0/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
Fixed version: Linux Linux 706e2bf330144995d123dccf32aaf1981ce5abc2, 9ecc4d033879f7761f2df07e20cd2fbec00fd90b.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 706e2bf330144995d123dccf32aaf1981ce5abc2, 9ecc4d033879f7761f2df07e20cd2fbec00fd90b or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: s390/pai: Support CPU hotplug for PMU PAI The command 'perf stat -e pai_crypto/CRYPTO_ALL/ -- <command>' crashes the kernel when CPUs are hotplug added during that run. Root cause is the missing allocation of per-CPU data structures for that new CPU. The allocation is dynamic and the first event that has task context creates such a structure for each online CPU. This is not sufficient. CPUs may be offline during event creation and can be set online during the perf run time. For example commands # echo 0 > /sys/devices/system/cpu/cpu1/online # perf stat -e cycles -i -- stress-ng -t10s --matrix X # sleep 1 # echo 1 > /sys/devices/system/cpu/cpu1/online Currently without a CPU hotplug handler, that new CPU has no per-CPU data infrastructure. The scheduler runs PMU call back function pai_add() to install the PMU support for that CPU before the task is being scheduled on that new CPU. In pai_add() instructions mp = this_cpu_ptr(pai_root[idx].mapptr); cpump = mp->mapptr; return a NULL pointer and the result is a kernel panic as variable cpump is used inside that function. Add CPU hotplug support for CPU add and delete and create the necessary per-CPU data infrastructure during CPU hotplug add processing. Same for CPU hotplug remove. This is done when the CPU is offline to ensure the data structures are available when CPU is made online and tasks are scheduled on it. [hca@linux.ibm.com: fixup error path in pai_init()]

—No exploit Fix available

EUVD-2026-86834

Published: Sep 25, 2026
Updated: Oct 19, 2026
EPSS: 0.1% · 8th percentile
CWE: —

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Action score

Monitor

Low priority for now.

CVSS: 0 / 40 · —
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 6.11affected
- 9f66572f2889a5e72a9d7e17787e52f03b1f7bd8 and later · before 706e2bf330144995d123dccf32aaf1981ce5abc2affected · git
- 9f66572f2889a5e72a9d7e17787e52f03b1f7bd8 and later · before 9ecc4d033879f7761f2df07e20cd2fbec00fd90baffected · git
- before 6.11not affected · semver
- 7.2.7 and later · up to and including 7.2.*not affected · semver
- 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:13	linux	from 0	—
Debian:14	linux	before 7.2.7-1	7.2.7-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
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CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
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CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
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Published before and after this one in the same product

← EarlierCVE-2026-97524Sep 25, 2026 · mptcp: avoid unneeded actions on subflow reset
30Monitor
← EarlierCVE-2026-97525Sep 25, 2026 · x86/mm/pat: Allocate split page tables as kernel page tables
32Monitor
Later →CVE-2026-97527Sep 25, 2026 · scsi: qla2xxx: Serialize NVMe unsol ctx list with a per-fcport lock
35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	706e2bf330144995d123dccf32aaf1981ce5abc2	Vendor (CNA)
Linux Linux	9ecc4d033879f7761f2df07e20cd2fbec00fd90b	Vendor (CNA)
debian:linux	7.2.7-1 · Debian:14	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).