High 7.0Published Apr 13, 2026

CVE-2026-31426ACPI: EC: clean up handlers on probe failure in acpi_ec_setup()

Updated under an hour ago (2026-10-19 07:23 UTC)

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In the Linux kernel, the following vulnerability has been resolved: ACPI: EC: clean up handlers on probe failure in acpi_ec_setup() When ec_install_handlers() returns -EPROBE_DEFER on reduced-hardware platforms, it has already started the EC and installed the address space handler with the struct acpi_ec pointer as handler context. However, acpi_ec_setup() propagates the error without any cleanup. The caller acpi_ec_add() then frees the struct acpi_ec for non-boot instances, leaving a dangling handler context in ACPICA. Any subsequent AML evaluation that accesses an EC OpRegion field dispatches into acpi_ec_space_handler() with the freed pointer, causing a use-after-free: BUG: KASAN: slab-use-after-free in mutex_lock (kernel/locking/mutex.c:289) Write of size 8 at addr ffff88800721de38 by task init/1 Call Trace: <TASK> mutex_lock (kernel/locking/mutex.c:289) acpi_ec_space_handler (drivers/acpi/ec.c:1362) acpi_ev_address_space_dispatch (drivers/acpi/acpica/evregion.c:293) acpi_ex_access_region (drivers/acpi/acpica/exfldio.c:246) acpi_ex_field_datum_io (drivers/acpi/acpica/exfldio.c:509) acpi_ex_extract_from_field (drivers/acpi/acpica/exfldio.c:700) acpi_ex_read_data_from_field (drivers/acpi/acpica/exfield.c:327) acpi_ex_resolve_node_to_value (drivers/acpi/acpica/exresolv.c:392) </TASK> Allocated by task 1: acpi_ec_alloc (drivers/acpi/ec.c:1424) acpi_ec_add (drivers/acpi/ec.c:1692) Freed by task 1: kfree (mm/slub.c:6876) acpi_ec_add (drivers/acpi/ec.c:1751) The bug triggers on reduced-hardware EC platforms (ec->gpe < 0) when the GPIO IRQ provider defers probing. Once the stale handler exists, any unprivileged sysfs read that causes AML to touch an EC OpRegion (battery, thermal, backlight) exercises the dangling pointer. Fix this by calling ec_remove_handlers() in the error path of acpi_ec_setup() before clearing first_ec. ec_remove_handlers() checks each EC_FLAGS_* bit before acting, so it is safe to call regardless of how far ec_install_handlers() progressed: -ENODEV (handler not installed): only calls acpi_ec_stop() -EPROBE_DEFER (handler installed): removes handler, stops EC

CVSS: 7.0 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Oct 16, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 03e9a0e05739cf872fee494b06c75c0469704a21 before 022d1727f33ff90b3e1775125264e3023901952e; from 03e9a0e05739cf872fee494b06c75c0469704a21 before 9c886e63b69658959633937e3acb7ca8addf7499; from 03e9a0e05739cf872fee494b06c75c0469704a21 before 808c0f156f48d5b8ca34088cbbfba8444e606cbc; from 03e9a0e05739cf872fee494b06c75c0469704a21 before d04c007047c88158141d9bd5eac761cdadd3782c; from 03e9a0e05739cf872fee494b06c75c0469704a21 before be1a827e15991e874e0d5222d0ea5fdad01960fe; from 03e9a0e05739cf872fee494b06c75c0469704a21 before f6484cadbcaf26b5844b51bd7307a663dda48ef6	CNA record
linux linux_kernel linux:linux_kernel	from 5.7 before 6.1.168; from 6.2 before 6.6.131; from 6.7 before 6.12.80; from 6.13 before 6.18.21; from 6.19 before 6.19.11; 5.7; 7.0; 7.0; and 4 more ranges	NVD

References

https://git.kernel.org/stable/c/022d1727f33ff90b3e1775125264e3023901952epatch
https://git.kernel.org/stable/c/9c886e63b69658959633937e3acb7ca8addf7499patch
https://git.kernel.org/stable/c/808c0f156f48d5b8ca34088cbbfba8444e606cbcpatch
https://git.kernel.org/stable/c/d04c007047c88158141d9bd5eac761cdadd3782cpatch
https://git.kernel.org/stable/c/be1a827e15991e874e0d5222d0ea5fdad01960fepatch
https://git.kernel.org/stable/c/f6484cadbcaf26b5844b51bd7307a663dda48ef6patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.