CVE-2026-31426 | Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10 kernel/locking/mutex.c acpi_ec_setup use after free

VDB-357153 · CVE-2026-31426 · EUVD-2026-21953 LINUX KERNEL UP TO 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10 KERNEL/LOCKING/MUTEX.C ACPI_EC_SETUP USE AFTER FREE HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 7.6 $5k-$25k 3.20+ Summaryinfo A vulnerability classified as critical has been found in Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10. Impacted is the function acpi_ec_setup of the file kernel/locking/mutex.c. Performing a manipulation results in use after free. This vulnerability was named CVE-2026-31426. There is no available exploit. It is recommended to upgrade the affected component. Detailsinfo A vulnerability was found in Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10. It has been classified as critical. This affects the function acpi_ec_setup of the file kernel/locking/mutex.c. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is: 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: 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) 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 The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-31426 since 03/09/2026. The exploitability is told to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 04/13/2026). Upgrading to version 6.1.168, 6.6.131, 6.12.80, 6.18.21 or 6.19.11 eliminates this vulnerability. Applying the patch 9c886e63b69658959633937e3acb7ca8addf7499/808c0f156f48d5b8ca34088cbbfba8444e606cbc/d04c007047c88158141d9bd5eac761cdadd3782c/be1a827e15991e874e0d5222d0ea5fdad01960fe/f6484cadbcaf26b5844b51bd7307a663dda48ef6 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version. The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-21953). Productinfo Type Operating System Vendor Linux Name Kernel Version 6.1.167 6.6.130 6.12.0 6.12.1 6.12.2 6.12.3 6.12.4 6.12.5 6.12.6 6.12.7 6.12.8 6.12.9 6.12.10 6.12.11 6.12.12 6.12.13 6.12.14 6.12.15 6.12.16 6.12.17 6.12.18 6.12.19 6.12.20 6.12.21 6.12.22 6.12.23 6.12.24 6.12.25 6.12.26 6.12.27 6.12.28 6.12.29 6.12.30 6.12.31 6.12.32 6.12.33 6.12.34 6.12.35 6.12.36 6.12.37 6.12.38 6.12.39 6.12.40 6.12.41 6.12.42 6.12.43 6.12.44 6.12.45 6.12.46 6.12.47 6.12.48 6.12.49 6.12.50 6.12.51 6.12.52 6.12.53 6.12.54 6.12.55 6.12.56 6.12.57 6.12.58 6.12.59 6.12.60 6.12.61 6.12.62 6.12.63 6.12.64 6.12.65 6.12.66 6.12.67 6.12.68 6.12.69 6.12.70 6.12.71 6.12.72 6.12.73 6.12.74 6.12.75 6.12.76 6.12.77 6.12.78 6.12.79 6.18.0 6.18.1 6.18.2 6.18.3 6.18.4 6.18.5 6.18.6 6.18.7 6.18.8 6.18.9 6.18.10 6.18.11 6.18.12 6.18.13 6.18.14 6.18.15 6.18.16 6.18.17 6.18.18 6.18.19 6.18.20 6.19.0 6.19.1 6.19.2 6.19.3 6.19.4 6.19.5 6.19.6 6.19.7 6.19.8 6.19.9 6.19.10 License open-source Website Vendor: https://www.kernel.org/ CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 8.0 VulDB Meta Temp Score: 7.6 VulDB Base Score: 8.0 VulDB Temp Score: 7.6 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Use after free CWE: CWE-416 / CWE-119 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Partially Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Kernel 6.1.168/6.6.131/6.12.80/6.18.21/6.19.11 Patch: 9c886e63b69658959633937e3acb7ca8addf7499/808c0f156f48d5b8ca34088cbbfba8444e606cbc/d04c007047c88158141d9bd5eac761cdadd3782c/be1a827e15991e874e0d5222d0ea5fdad01960fe/f6484cadbcaf26b5844b51bd7307a663dda48ef6 Timelineinfo 03/09/2026 CVE reserved 04/13/2026 +34 days Advisory disclosed 04/13/2026 +0 days VulDB entry created 04/13/2026 +0 days VulDB entry last update Sourcesinfo Vendor: kernel.org Advisory: git.kernel.org Status: Confirmed CVE: CVE-2026-31426 (🔒) GCVE (CVE): GCVE-0-2026-31426 GCVE (VulDB): GCVE-100-357153 EUVD: 🔒 Entryinfo Created: 04/13/2026 16:05 Updated: 04/13/2026 17:58 Changes: 04/13/2026 16:05 (59), 04/13/2026 17:58 (1) Complete: 🔍 Cache ID: 99:180:101 Discussion No comments yet. 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