# CVE-2026-81016

## Summary

- **CVE ID:** CVE-2026-81016
- **Severity:** HIGH
- **CVSS Score:** 7.7 (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:

platform/x86/amd/pmc: Propagate SMU errors and validate S2D address

amd_stb_s2d_init() discards the return value of several S2D SMU commands.
When the SMU refuses a command (e.g. "SMU cmd failed. err: 0xff") the
failure is only noticed indirectly - if at all - and reported as -EIO,
masking the real error.

More seriously, the S2D_PHYS_ADDR_LOW/HIGH return values are ignored, so
on failure phys_addr_low/hi are left uninitialised and the assembled
address is passed straight to devm_ioremap().  When the SMU leaves them at
zero this maps physical address 0 and trips the ioremap-on-RAM warning:

  amd_pmc AMDI000B:00: SMU cmd failed. err: 0xff
  ioremap on RAM at 0x0000000000000000 - 0x0000000000ffffff
  WARNING: CPU: 13 PID: 4592 at arch/x86/mm/ioremap.c:...

Check the return value of each SMU command and propagate it, and reject a
zero physical address before calling devm_ioremap().

## Affected Products

- Linux — Linux (3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d)
- Linux — Linux (5.18)
- Linux — Linux (0)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/8178f59d76570b152d836bde07f5997f15861f04)
- [CNA](https://git.kernel.org/stable/c/775d4cde1f9737796ce7d8393521e9e8c5b49891)
- [CNA](https://git.kernel.org/stable/c/0225c1d637687b03726f00ac65b6def843d2c464)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 7.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._