CVE-2026-99017: Linux kernel · riscv: errata: select RISCV_ALTERNATIVE_EARLY for THEAD GHOSTWRITE
Source GCVE Database
Not known to be exploited · CVSS 7.0 High · fixed in fa465a7819ecbe5801b78c088d3cadaf2664b8ca : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in fa465a7819ecbe5801b78c088d3cadaf2664b8ca, 298510bbc7c3017c0faf481c6ea66f1065b657b4, 7fee577a2fa78b9a76da015beec1ccf978746ebb
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Linux kernel to fa465a7819ecbe5801b78c088d3cadaf2664b8ca, 298510bbc7c3017c0faf481c6ea66f1065b657b4 or 7fee577a2fa78b9a76da015beec1ccf978746ebb.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-99017 (opens in a new tab)
- git.kernel.org/stable/c/298510bbc7c3017c0faf481c6ea66f1065b657b4 (opens in a new tab)
- git.kernel.org/stable/c/7fee577a2fa78b9a76da015beec1ccf978746ebb (opens in a new tab)
- git.kernel.org/stable/c/fa465a7819ecbe5801b78c088d3cadaf2664b8ca (opens in a new tab)