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CVE-2026-98546

In the Linux kernel, the following vulnerability has been resolved: arm64/boot: Disable trapping of PMZR_EL0 writes to EL2 __init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.

Published Oct 18, 2026EPSS 0.20%

Overview

CVE-2026-98546 is a known-severity vulnerability. It was published on October 18, 2026.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

arm64/boot: Disable trapping of PMZR_EL0 writes to EL2

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.

PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in

HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host

traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The

kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU

driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a

write from EL0 reaches the trap and takes the host down without a panic

message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already

does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9

bits.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently asked questions

What is CVE-2026-98546?

CVE-2026-98546 is a known-severity vulnerability. It was published on October 18, 2026.

How severe is CVE-2026-98546?

CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.

How do I fix or remediate CVE-2026-98546?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-98546?

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