CVE-2026-31426
Description
A flaw was found in the Linux kernel's Advanced Configuration and Power Interface (ACPI) Embedded Controller (EC) subsystem. During the setup of the EC handler, if a probe deferral occurs on specific hardware, the system fails to properly deallocate resources. This oversight creates a use-after-free vulnerability, allowing an unprivileged local attacker to trigger a system crash, resulting in a Denial of Service (DoS). The attacker can exploit this by performing certain system file system (sysfs) reads that interact with EC OpRegion fields.
Statement
This affects reduced-hardware EC setups where probe defers after the handler is partially installed. The patch removes handlers on the error path before dropping the EC object. Follow-on AML can be triggered from paths including sysfs-driven configuration reads; impact is at least denial of service via crash, and memory corruption warrants manual review for any broader confidentiality or integrity claim.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.8 | N/A | 7 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | High |
| Integrity Impact | Low | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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