# CVE-2026-89459

## Summary

- **CVE ID:** CVE-2026-89459
- **Severity:** HIGH
- **CVSS Score:** 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## Description

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

s390/percpu: Fix MVIY_PERCPU() with older binutils

Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient
this_cpu operations") introduced MVIY_PERCPU(), which stringifies
arguments that are already C string literals. This generates an
assembler macro invocation with whitespace-separated quoted arguments:

  GEN_MVIY "459712" "%r3"

GNU as versions prior to binutils 2.39 drop the separating whitespace
between quoted macro arguments during input scrubbing. They
consequently parse the invocation as a single argument and emit
repeated warnings:

  Warning: missing closing `"'

The .ifc in GEN_MVIY never matches and GNU as exits successfully
without emitting the mviy instruction. As a result, the interrupted
per-CPU sequence is not marked in lowcore and the exception return
path cannot repair the per-CPU address register after migration.

All MVIY_PERCPU() callers pass C string literals. Use them directly
and separate the assembler macro arguments with an explicit comma. The
resulting invocation is:

  GEN_MVIY 459712, %r3

This form is unambiguous for GNU as and LLVM's integrated assembler.
This behavior was fixed in GNU as from binutils 2.39, but Linux
supports binutils 2.30.

## Affected Products

- Linux — Linux (a737737cdb9c94e40a9926cdc2320f874c05d709)
- Linux — Linux (7.2)
- Linux — Linux (0)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/91770b08a120967077ae78600612f18bc5ee3caf)
- [CNA](https://git.kernel.org/stable/c/101782f8945a125044347312d74d488c05741c4a)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.11%
- **EPSS Percentile:** 1.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._