# CVE-2026-46290: x86/efi: Fix graceful fault handling after FPU softirq changes

> A logic error in Linux kernel EFI fault handling causes system freezes on buggy firmware, requiring a patch to restore graceful recovery.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jun 2026
- **Updated:** 14 Jun 2026
- **Also known as:** BELL-CVE-2026-46290, DEBIAN-CVE-2026-46290, GHSA-qr7g-p698-q8wm, UBUNTU-CVE-2026-46290

## What is CVE-2026-46290?

CVE-2026-46290 is a medium-severity denial of service vulnerability in Linux kernel, published on 8 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

x86/efi: Fix graceful fault handling after FPU softirq changes

Since commit d02198550423 ("x86/fpu: Improve crypto performance by
making kernel-mode FPU reliably usable in softirqs"), kernel_fpu_begin()
calls fpregs_lock() which uses local_bh_disable() instead of the
previous preempt_disable(). This sets SOFTIRQ_OFFSET in preempt_count
during the entire EFI runtime service call, causing in_interrupt() to
return true in normal task context.

The graceful page fault handler efi_crash_gracefully_on_page_fault()
uses in_interrupt() to bail out for faults in real interrupt context.
With SOFTIRQ_OFFSET now set, the handler always bails out, leaving EFI
firmware page faults unhandled. This escalates to die() which also sees
in_interrupt() as true and calls panic("Fatal exception in interrupt"),
resulting in a hard system freeze. On systems with buggy firmware that
triggers page faults during EFI runtime calls (e.g., accessing unmapped
memory in GetTime()), this causes an unrecoverable hang instead of the
expected graceful EFI_ABORTED recovery.

Fix by replacing in_interrupt() with !in_task(). This preserves the
original intent of bailing for interrupts or NMI faults, while no longer
falsely triggering from the FPU code path's local_bh_disable().

[ardb: Sashiko spotted that using 'in_hardirq() || in_nmi()' leaves a
       window where a softirq may be taken before fpregs_lock() is
       called, but after efi_rts_work.efi_rts_id has been assigned,
       and any page faults occurring in that window will then be
       misidentified as having been caused by the firmware. Instead,
       use !in_task(), which incorporates in_serving_softirq(). ]

## Which versions are affected by CVE-2026-46290?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46290?

Apply the vendor's patch.

## Is CVE-2026-46290 being exploited?

There is no known exploitation of CVE-2026-46290 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46290 and fix it if it is affected.

What it is: CVE-2026-46290 is a medium-severity denial of service vulnerability in Linux kernel, published on 8 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-46290 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-46290/ (Markdown: https://insights.sbomify.com/CVE-2026-46290/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46290
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46290
- OSV: https://osv.dev/vulnerability/CVE-2026-46290

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46290/
Summaries are generated and may contain mistakes; the official description above is the record.