CVE-2026-90009 Linux Kernel - Time-of-Check to Time-of-Use (TOCTOU)

Linux kernel contains a time-of-check to time-of-use (TOCTOU) vulnerability in scsi bsg io_uring passthrough command setup caused by unsynchronized access to shared mmap'd SQE fields, letting attackers cause buffer overflow, exploit requires userspace to modify shared memory after validation.

CVSS base score 7.8 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.17% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Time-of-Check to Time-of-Use (TOCTOU)
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
16 September 2026
Updated
15 October 2026

Vendor fix

Update to the latest Linux kernel version with the TOCTOU fix applied.

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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