CVE-2026-43261

Vulnerability

CVE-2026-43261 addresses a Spectre-BHB (Branch History Buffer) vulnerability in the TSV110 ARM processor. Spectre-BHB is a side-channel attack that allows an attacker to infer sensitive information by manipulating the branch history buffer and observing subsequent branch prediction behavior. The TSV110 CPU is susceptible to this attack, potentially leaking data across security boundaries.

Exploitation

An attacker with local access or the ability to execute arbitrary code on a system using the TSV110 processor can exploit this vulnerability. The attack typically requires knowledge of the processor's branch predictor implementation and the ability to run code in the same CPU context, such as from an unprivileged process or within a container. No authentication is needed beyond the ability to execute code [1].

Impact

Successful exploitation could result in information disclosure, allowing an attacker to read sensitive data from the kernel or other processes. This may include cryptographic keys, passwords, or other confidential information, potentially leading to further compromise of the system.

Mitigation

The Linux kernel commit adds the TSV110 processor's MIDR (Main ID Register) to the list of CPUs that require a software-based Spectre-BHB mitigation. This ensures that the kernel applies the appropriate workaround (such as clearing the branch history buffer) on affected systems. System administrators should update their kernels to include this fix [1]. No hardware changes are required.