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CVE-2026-80665
KVM: arm64: nv: Inject SEA if kvm_translate_vncr() can't resolve PFN
Published 2026-08-28 (2 months ago) by the Linux kernel CNA. Subsystem arch/arm64. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-80665 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 | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
kvm_handle_vncr_abort() assumes that s1_walk_result conveys an abort when kvm_translate_vncr() returns -EFAULT. This is not always the case as it's possible to encounter 'late' failures on the output of S1 translation, e.g. a GFN outside of the memslots. Fix it by preparing an external abort before returning from kvm_translate_vncr(). Get rid of the BUG_ON() in the fault injection path while at it.
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.
arch/arm64/include/asm/kvm_nested.h
arch/arm64/kvm/at.c
arch/arm64/kvm/nested.c
- What this is
- KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)MAINTAINERS section matched on arch/arm64/include/asm/kvm* · linux-arm-kernel@lists.infradead.org · Maintained
- Kernel module
- kvm
Check it on the machine
grep -w CONFIG_KVM /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w kvmPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixieBnot built on armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- forky, sidBnot built on armhf/armmp, armhf/armmp-lpae
- ?
- not established - no Makefile entry for the affected file
- B
- built in on some, a module on others, absent on the rest
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.
- Build switch
- CONFIG_KVM
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 kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-28 (2 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.21%, higher than 10.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- arch/arm64
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.16 | 6.18.40 | 4ead4def0465 |
| 6.16 | 7.1.5 | 53804b683957 |
| 6.16 | 7.2 | 9f3e83345a56 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The bug is reached only when an arm64 nested-KVM L1 hypervisor triggers VNCR_EL2 data aborts (ESR_ELx_EC_DABT_CUR with ESR_ELx_VNCR) during KVM_RUN via kvm_handle_vncr_abort(); no network, adjacent-radio, or physical-device path reaches this code.
- AC:LAttack complexity, low
- An attacker controlling an L1 nested-hypervisor VM can reliably set VNCR_EL2 and guest EL2 page tables so stage-1 translation succeeds but the resulting GFN is outside host memslots or PFN resolution fails, deterministically hitting the faulty -EFAULT path; nested virt on arm64 cloud hosts is an attacker-selectable deployment.
- PR:NPrivileges required, none
- Exploitation requires no host root or init-namespace capabilities beyond running hypervisor code in a tenant KVM guest on an arm64 host with nested virtualization enabled; the attacker operates entirely from within their assigned VM, consistent with other arm64 KVM nested-virt CVE scoring.
- UI:NUser interaction, none
- No victim user or administrator action is required beyond the attacker operating their own nested-virtualization workload; VNCR faults, page-table configuration, and repeated translation triggers are fully attacker-driven from within the guest.
- S:CScope, changed
- A malicious nested guest forces host KVM into BUG_ON(!vt->wr.failed) during VNCR abort handling, crashing the physical host kernel and denying service to all co-resident VMs, crossing the guest-to-hypervisor security boundary beyond the guest's intended authority.
- C:NConfidentiality impact, none
- The vulnerability triggers a host kernel BUG_ON panic on a late translation failure without setting s1_walk_result.failed; there is no out-of-bounds read, use-after-free, or other information-disclosure primitive—only an incorrect assumption leading to host crash.
- I:NIntegrity impact, none
- Impact is limited to host kernel panic via BUG_ON on the fault-injection path; no guest or host data is modified, no arbitrary write primitive exists, and the fix only prepares an external abort for reinjection to the nested guest.
- A:HAvailability impact, high
- BUG_ON(!vt->wr.failed) on the late -EFAULT path causes an uncontained host kernel panic on production kernels (CONFIG_BUG=y), crashing the hypervisor and denying availability to every workload on the affected physical machine; the attacker can retrigger after reboot.