Linux Kernel up to 7.2.5 Arm64 Entry entry-common.c arm64_exit_to_kernel_mode state issue

Summaryinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.2.5. This affects the function arm64_exit_to_kernel_mode of the file arch/arm64/kernel/entry-common.c of the component Arm64 Entry Handler. Such manipulation leads to state issue. This vulnerability is uniquely identified as CVE-2026-93254. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been rated as very critical. Affected by this issue is the function arm64_exit_to_kernel_mode of the file arch/arm64/kernel/entry-common.c of the component Arm64 Entry Handler. The manipulation with an unknown input leads to a state issue vulnerability. Using CWE to declare the problem leads to CWE-371. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit Currently, when exiting to kernel mode, we attempt involuntary preemption. The preemption logic expects IRQs to be disabled, which is why we call local_irq_disable() before attempting preemption. However, depending on the context, local_irq_disable() may be unnecessary: - __el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so local_irq_disable() is redundant. - irqentry_exit_to_kernel_mode_preempt() immediately returns when exiting from an NMI-like context, so calling local_irq_disable() beforehand is unnecessary work. Furthermore, it confuses the pNMI state tracking when we are in a context with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set in the PMR, leading to a warning when CONFIG_ARM64_DEBUG_PRIORITY_MASKING=y: WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805 CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--) pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) lr : el1_abort (arch/arm64/kernel/entry-common.c:323) pmr: 000000f0 Call trace: arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P) el1_abort (arch/arm64/kernel/entry-common.c:323) el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449) el1h_64_sync (arch/arm64/kernel/entry.S:589) [...] Split arm64_exit_to_kernel_mode() into preempt, non-preempt, and dispatch parts so that we can avoid this extra work where it is not needed and avoid breaking the pNMI tracking logic.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-93254 since 09/17/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/24/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch 49a61174186bed25d439ff37400c7ce5e3603e73/39aebe0e89469c2904e60b1e977e0d4dbf33326b is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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