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CVE-2026-97455
ACPICA: Fix use-after-free in acpi_ds_terminate_control_method()
Published 2026-09-24 (24 days ago) by the Linux kernel CNA. Subsystem drivers/acpi. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-97455 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Fix use-after-free issue in acpi_ds_terminate_control_method() by clearing references to method locals and arguments.
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.
drivers/acpi/acpica/dsmethod.c
- What this is
- ACPI COMPONENT ARCHITECTURE (ACPICA)MAINTAINERS section matched on drivers/acpi/acpica/ · linux-acpi@vger.kernel.org · Supported
Check it on the machine
grep -w CONFIG_ACPI /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.
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.
- bookwormYnot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
- trixieYnot built on armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- forky, sidYnot built on armhf/armmp, armhf/armmp-lpae, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- bookworm · linux-6.12Ynot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- Y
- built in where it is built at all; some flavours do not build it
- Build switch
- CONFIG_ACPI
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
- 2026-09-24 (24 days ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 3.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/acpi
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.12 | 5.10.271 | 460aed7b4085 |
| 2.6.12 | 5.15.222 | 3855d8992f5a |
| 2.6.12 | 6.1.189 | 2793b1c38f00 |
| 2.6.12 | 6.6.158 | 63ca6f67816a |
| 2.6.12 | 6.12.111 | fe7b3d3b7490 |
| 2.6.12 | 6.18.53 | ef5a8d939c1e |
| 2.6.12 | 7.2 | 945e87267cfd |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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 data that becomes walk_state->return_desc is AML RefOf(Local/Arg) in the platform DSDT/SSDT. acpi_ex_get_object_reference builds that ACPI_REFCLASS_REFOF; acpi_ps_parse_aml then calls the patched acpi_ds_terminate_control_method from acpi_ns_execute_table (acpi_load_tables) or acpi_ps_execute_method (acpi_evaluate_object). Those tables are local firmware, not a network protocol message.
- AC:LAttack complexity, low
- The table author emits Return(RefOf(LocalN)) or Return(RefOf(ArgN)); acpi_ex_get_object_reference sets reference.object to &walk_state->local_variables[i] or &walk_state->arguments[i]. acpi_ds_terminate_control_method then acpi_ds_method_data_delete_all, acpi_ps_parse_aml still forwards return_desc, and acpi_ds_delete_walk_state frees the node. That sequence is deterministic with no race.
- PR:NPrivileges required, none
- acpi_bus_init calls acpi_load_tables → acpi_tb_load_namespace → acpi_ns_load_table → acpi_ns_execute_table with no uid or capability check. Module-level AML that invokes a nested method returning RefOf(Local/Arg), with the caller Store/DerefOf using that value, hits acpi_ds_terminate_control_method at boot before any account exists.
- UI:NUser interaction, none
- acpi_ns_execute_table runs that nested Return(RefOf(Local/Arg)) automatically during acpi_load_tables in acpi_bus_init at power-on; the victim does not mount media, open a file, or otherwise interact.
- S:UScope, unchanged
- The dangling ACPI_REFCLASS_REFOF points at the embedded local_variables[]/arguments[] acpi_namespace_node inside the kmalloc'd acpi_walk_state freed by acpi_ds_delete_walk_state; that is host ACPICA heap corruption, not a KVM/Xen, IOMMU, or sandbox crossing.
- C:HConfidentiality impact, high
- After acpi_ds_delete_walk_state, acpi_ns_resolve_references reads node->object from the freed local/arg pseudo-node, and a parent DerefOf uses operand[0]->reference.object the same way; that use-after-free of the walk_state slab is an arbitrary kernel-memory read, not a few-byte leak.
- I:HIntegrity impact, high
- A parent Store to the returned RefOf calls acpi_ex_store_object_to_node on the dangling node, and acpi_ns_resolve_references does acpi_ut_add_reference on node->object taken from freed walk_state memory; spraying that slab yields a write/refcount primitive and control-flow hijack.
- A:HAvailability impact, high
- acpi_ds_delete_walk_state frees the walk_state while return_desc still aliases its local_variables[]/arguments[] nodes; later ns_resolve_references or DerefOf/Store through that pointer oopses or panics, and any use-after-free is Availability High.