CVE-2026-99018 Linux Kernel - Broken Access Control

Linux kernel contains a broken access control vulnerability caused by improper determination of user mode entry using tp register instead of sstatus.SPP bit in riscv entry, letting unprivileged attackers achieve arbitrary kernel write and control-flow hijack, exploit requires CONFIG_SHADOW_CALL_STACK enabled.

CVSS base score 7.8 /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
Broken Access Control
Impact
Data Tampering
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
23 October 2026
Updated
25 October 2026

Vendor fix

Update to the latest Linux kernel version containing 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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