CVE-2026-31389
Published: 03 April 2026
Summary
CVE-2026-31389 is a high-severity Use After Free (CWE-416) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 4.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-31389 is a use-after-free vulnerability in the Linux kernel's SPI subsystem. It arises during SPI controller registration when per-CPU statistics allocation fails, leading to improper handling that can result in use-after-free of driver resources and unclocked register accesses. The issue affects the Linux kernel and carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
A local attacker with low privileges can exploit this vulnerability through low-complexity means without requiring user interaction. Exploitation could grant high-impact access to confidential data, modification of system integrity, and denial-of-service via availability disruption, such as through arbitrary code execution or kernel crashes triggered by the use-after-free.
Mitigation involves applying patches from Linux kernel stable repositories, as detailed in the referenced commits: 0e23f50086da7d0b183dfeac26021acfcdee086b, 23b51bad2eb8787aa74324cfccefb258515ae5ba, 6bbd385b30c7fb6c7ee0669e9ada91490938c051, 80f3e8cd2b4ad355b2ad2024cf423f6d183404f7, and 8634e05b08ead636e926022f4a98416e13440df9. These fixes ensure deregistration from the driver core occurs even if allocation fails during registration.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18761
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: spi: fix use-after-free on controller registration failure Make sure to deregister from driver core also in the unlikely event that per-cpu statistics allocation fails during controller registration to avoid use-after-free…
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(of driver resources) and unclocked register accesses.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Use-after-free in Linux kernel SPI subsystem directly enables local privilege escalation via arbitrary code execution or kernel-level access from low-privileged context.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely patching of the use-after-free flaw in the Linux kernel SPI controller registration process.
Mandates fail-safe procedures during resource allocation failures to ensure proper deregistration and avoid use-after-free.
Implements memory safeguards that mitigate exploitation of the use-after-free vulnerability for code execution or crashes.