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CVE-2026-98546
arm64/boot: Disable trapping of PMZR_EL0 writes to EL2
Published 2026-10-18 (today) by the Linux kernel CNA. Subsystem Documentation/arch. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-98546 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | fixed | 6.12.113-1 | Update the kernel and reboot. Fixed in 6.12.113-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.9-1 | Update the kernel and reboot. Fixed in 7.2.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.9-1 | Update the kernel and reboot. Fixed in 7.2.9-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
__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.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
Documentation/arch/arm64/booting.rst
arch/arm64/include/asm/el2_setup.h
- What this is
- ARM64 PORT (AARCH64 ARCHITECTURE)MAINTAINERS section matched on Documentation/arch/arm64/ · linux-arm-kernel@lists.infradead.org · Maintained
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS
Signals
- Published
- 2026-10-18 (today)source
- CVSS
- no vector published, unrated
- Attack vector
- not published
- EPSS
- not scored
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- Documentation/arch
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.12.25 | 6.12.112 | bb8c90c86441 |
| 6.15 | 6.18.55 | 071f51188a5d |
| 6.15 | 7.2.9 | ce71865bf43f |
| 6.15 | 7.3 | 2bc6b218717b |
| 6.14.4 | 0 | 0 |
Why the CNA scored it this way
The kernel CNA published no CVSS vector and no reasoning for CVE-2026-98546, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.