Описание
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.
A flaw was found in the Linux kernel. Under specific configurations on RISC-V systems using T-Head processors, the kernel does not execute early boot checks required to identify hardware errata. As a result, the default mitigation for the Ghostwrite hardware vulnerability is not applied, which may allow a local attacker to exploit unmitigated CPU flaws to access unauthorized data or compromise system integrity.
Отчет
This vulnerability is rated as Moderate impact because exploitation requires local access on specific hardware architectures and depends on an uncommon kernel compile-time configuration. Standard Red Hat Enterprise Linux distributions do not support or distribute kernels for the RISC-V architecture, meaning Red Hat environments are not directly affected by this flaw. On platforms where applicable, bypassing early processor errata discovery prevents runtime mitigation of the Ghostwrite issue, leaving unprivileged local processes capable of corrupting system memory.
Меры по смягчению последствий
--- CME Mitigation Guidance (2026-11-02) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure. The highest-value action is to enable early boot alternatives probing by ensuring CONFIG_RISCV_ALTERNATIVE_EARLY is active in kernel builds supporting T-Head Ghostwrite errata mitigations: upgrade to the fixed Kernel/Kernel Ivos Qualcomm builds, which select RISCV_ALTERNATIVE_EARLY automatically when ERRATA_THEAD_GHOSTWRITE is enabled in Kconfig, closing execution of xtheadvector instruction sequences by an unprivileged local user. Until patched, this is only a concern on RISC-V systems utilizing vulnerable T-Head C9xx processors running kernels configured with CONFIG_ERRATA_THEAD_GHOSTWRITE=y and CONFIG_ERRATA_THEAD_MAE=n — Non-RISC-V architectures and standard Red Hat Enterprise Linux distributions that do not support RISC-V are unaffected — so Restrict untrusted local user access and execution on affected RISC-V hosts, or recompile the kernel with CONFIG_ERRATA_THEAD_MAE=y so early alternatives execute. As a compensating measure, Deploy SELinux in enforcing mode to confine compromised processes to their domain if Ghostwrite memory corruption occurs and Map unprivileged local user sessions to confined SELinux domains to restrict post-exploitation access following hardware memory manipulation. These controls limit blast radius and contain exploitation, but they do not fix the underlying missing early boot errata selection defect — apply the upstream patch to fully remediate. Highest-impact CME: CME-301 SELinux (Enforcing Mode) (medium)
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Not affected |
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Дополнительная информация
Статус:
EPSS
7 High
CVSS3
Связанные уязвимости
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 ap...
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 a
In the Linux kernel, the following vulnerability has been resolved: r ...
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 i...
EPSS
7 High
CVSS3