VulnerabilityPublished 18 Oct 2026

CVE-2026-98546: Linux kernel · arm64/boot: Disable trapping of PMZR_EL0 writes to EL2

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in ce71865bf43f88bed9d9218e9218e537150be506 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in ce71865bf43f88bed9d9218e9218e537150be506, bb8c90c86441c090e9036f019cf1b4d7894a2c40, 071f51188a5d8ec10535541255587976d12fc7d8 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=6.12.25 <6.12.112 >=6.14.4 <6.15	Fixed in ce71865bf43f88bed9d9218e9218e537150be506 bb8c90c86441c090e9036f019cf1b4d7894a2c40 071f51188a5d8ec10535541255587976d12fc7d8 6.15 6.12.112 2bc6b218717b9d08f466f88209251d54bc09b207
LinuxLinux	Affected =6.15	Fixed in–

AI-suggested

This vulnerability has been fixed in Linux kernel versions 6.12.112, 6.15, and later commits identified by hashes ce71865bf43f88bed9d9218e9218e537150be506, bb8c90c86441c090e9036f019cf1b4d7894a2c40, 071f51188a5d8ec10535541255587976d12fc7d8, and 2bc6b218717b9d08f466f88209251d54bc09b207. Users should upgrade to these fixed versions to remediate the issue.

Description

A vulnerability in the Linux kernel arm64 architecture involves improper handling of PMZR_EL0 writes to EL2. The kernel traps these writes due to a missing trap bit setting, causing the host to crash without a panic message when certain user-space performance monitoring events are accessed. This issue affects specific Linux kernel versions and has been fixed in later releases.

Impact

The vulnerability can cause the host system to crash silently without a panic message when a user-level task performs a PMZR_EL0 write under specific performance monitoring conditions. This results in a denial of service on affected Linux kernel versions.

Summary

The vulnerability arises because the kernel function __init_el2_fgt2() writes a mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2 registers, but the trap bit for PMZR_EL0 writes (nPMZR_EL0) exists only in HDFGWTR2_EL2 and was never set. Consequently, a PMZR_EL0 write from the host traps to EL2, where the nVHE hypervisor lacks a handler, triggering a BUG() and crashing the host silently. Although the kernel does not write PMZR_EL0, enabling kernel.perf_user_access=1 causes the PMU driver to set PMUSERENR_EL0.UEN for tasks with user-read events, allowing a user-level write to trigger the trap and crash. The fix involves accumulating HDFGWTR2_EL2 bits separately and setting nPMZR_EL0 along with other FEAT_PMUv3p9 bits.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 10:40 UTC

Technical details

References

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