CVE-2026-99017

Description

In the Linux kernel, the following vulnerability has been resolved: riscv: errata: select RISCV_ALTERNATIVE_EARLY for THEAD GHOSTWRITE errata_probe_ghostwrite() only marks the CPU as vulnerable when it is called at the RISCV_ALTERNATIVES_EARLY_BOOT stage, and the mitigation in ghostwrite_enable_mitigation() only takes effect if the vulnerable state was recorded before the boot alternatives are patched. The early boot stage is only executed when CONFIG_RISCV_ALTERNATIVE_EARLY is enabled, which currently is only selected by ERRATA_THEAD_MAE. In a kernel built with ERRATA_THEAD_GHOSTWRITE=y but ERRATA_THEAD_MAE=n, the early alternatives never run, so ghostwrite_state is never set to VULNERABLE: ghostwrite_enable_mitigation() returns false, xtheadvector remains enabled, and sysfs reports "Not affected" on a vulnerable T-Head C9xx CPU. Select RISCV_ALTERNATIVE_EARLY from ERRATA_THEAD_GHOSTWRITE so that the vulnerability is detected in the early boot stage and the default mitigation is applied.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

References

• https://git.kernel.org/stable/c/fa465a7819ecbe5801b78c088d3cadaf2664b8ca ↗
• https://git.kernel.org/stable/c/7fee577a2fa78b9a76da015beec1ccf978746ebb ↗
• https://git.kernel.org/stable/c/298510bbc7c3017c0faf481c6ea66f1065b657b4 ↗