Race condition in Linux kernel - CVE-2026-99178
Published: October 29, 2026
Vulnerability identifier: #VU158406
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-99178
CWE-ID: CWE-362
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service by triggering a kernel panic in a KVM guest.
The vulnerability exists due to a race condition in the Linux kernel's x86 KVM asynchronous page-fault handler when a kernel-mode page fault in NMI context consumes pending asynchronous page-fault reason flags belonging to an interrupted handler. A local user can run perf sampling with user call chains and an invalid user-space frame pointer to trigger a guest kernel panic if the sampling NMI faults during the interval between asynchronous page-fault delivery and consumption of its reason flags.
Affected software
Linux kernel
Debian Linux
linux (Debian package)
Debian Linux
linux (Debian package)
How to mitigate CVE-2026-99178
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
linux (Debian package) - update to 6.12.115-2
linux (Debian package) - update to 6.12.115-2