---
cve: "CVE-2026-99017"
severity: "HIGH"
cvss: 7.0
epss: "0.2%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-10-23 13:17:24"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-11-04T14:09:27+01:00"
---

# CVE-2026-99017

> 7.0 HIGH

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **Linux**
- State: PUBLISHED
- Stand: 2026-10-24 14:10:04
- CNA-CVSS: **7.0** (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Hoch | good |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 6.18.57
- Kernel ≥ 7.2.11

## Referenzen

- <https://git.kernel.org/stable/c/fa465a7819ecbe5801b78c088d3cadaf2664b8ca>
- <https://git.kernel.org/stable/c/7fee577a2fa78b9a76da015beec1ccf978746ebb>
- <https://git.kernel.org/stable/c/298510bbc7c3017c0faf481c6ea66f1065b657b4>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-99017/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_