CVE-2026-99017 Linux Kernel - Privilege Escalation

Linux kernel contains a privilege escalation vulnerability caused by improper early boot stage detection in RISCV_ALTERNATIVE_EARLY for THEAD GHOSTWRITE, letting attackers bypass mitigation on vulnerable T-Head C9xx CPUs, exploit requires specific kernel configuration.

CVSS base score 7.0 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.21% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Privilege Escalation
Impact
Privilege Escalation
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
23 October 2026
Updated
25 October 2026

Vendor fix

Enable RISCV_ALTERNATIVE_EARLY selection in ERRATA_THEAD_GHOSTWRITE and update to the latest kernel version with the fix.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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