— Unscored

In the Linux kernel, the following vulnerability has been resolved: x86/kvm: Don't consume async #PF flags on a kernel #PF in NMI context…

CVE-2026-99178

In the Linux kernel, the following vulnerability has been resolved: x86/kvm: Don't consume async #PF flags on a kernel #PF in NMI context An async #PF "page not present" event arrives through the #PF vector, and its reason sits in the per-CPU apfreason.flags until kvmhandleasyncpf() reads and clears it. If an NMI arrives after the event is injected and before the #PF handler reads the flags, and the NMI handler itself takes a #PF, that fault reads and clears the flags belonging to the #PF it interrupted. It then finds interrupts disabled in the NMI context it interrupted, and panics: Kernel panic - not syncing: Host injected async #PF in interrupt disabled region Call Trace: panic+0x52/0x60 kvmhandleasyncpf+0xb0/0xb0 excpagefault+0x71/0xb0 asmexcpagefault+0x27/0x30 RIP: 0010:getusernocheck8+0x6/0x20 perfcallchainuser+0x147/0x1a0 getperfcallchain+0x12d/0x1c0 ... perfeventnmihandler+0x26/0x50 excnmi+0xe8/0x110 RIP: 0010:asmexcpagefault+0x0/0x30 The last RIP line shows the NMI landing on the first instruction of the #PF entry. perf with user call chains takes such a fault: the sampling NMI walks the user stack with getuser(), which faults when a saved frame pointer is not a valid…

Assessment

CVSS: Not yet scored
Severity: Unscored
EPSS: 0.17% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 28 October 2026
Last updated: 1 November 2026
Affected: Linux
Assigner: Linux

At the source

EUVD (ENISA)

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