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CVE-2026-46290 Linux CVE debrief

A vulnerability in the Linux kernel's x86/efi component has been identified. The issue arises from a change in kernel_fpu_begin() calls fpregs_lock(), which uses local_bh_disable() instead of preempt_disable(). This causes in_interrupt() to return true in normal task context, leading the graceful page fault handler efi_crash_gracefully_on_page_fault() to bail out and escalate to die(), resulting in a hard system freeze. The fix replaces in_interrupt() with !in_task() to preserve the original intent of bailing for interrupts or NMI faults.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-08
Original CVE updated
2026-07-23
Advisory published
2026-06-08
Advisory updated
2026-07-23

Who should care

Linux kernel developers and users, particularly those using x86/efi systems, should be aware of this vulnerability.

Technical summary

The vulnerability is caused by a change in the Linux kernel's x86/efi component. Specifically, the kernel_fpu_begin() function calls fpregs_lock(), which uses local_bh_disable() instead of preempt_disable(). This sets SOFTIRQ_OFFSET in preempt_count during EFI runtime service calls, causing in_interrupt() to return true in normal task context. As a result, the efi_crash_gracefully_on_page_fault() function bails out, leading to a hard system freeze.

Defensive priority

High

Recommended defensive actions

  • Apply the fix by replacing in_interrupt() with !in_task() in the efi_crash_gracefully_on_page_fault() function.
  • Use official kernel updates or patches when available.

Evidence notes

The vulnerability was resolved by a commit in the Linux kernel. References to the commit and related discussions are available through the following links:

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46290 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46290

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-46290 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46290

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/088f65e206087bf903743bd18417261d7a4c9644

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/22b365ba1af3d8c6036b8e5112fffe80998b85a0

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/db155b86d1523e85941f61efd7d7ffb594cc9a29

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.