Why isn't my CPU temperature showing?

The short version

Reading the temperature of a CPU or GPU die requires kernel-level access to the hardware. For years, most monitoring tools got that access through a small shared driver called WinRing0. That driver has a known vulnerability, and Microsoft now blocks it by default on modern Windows. When the driver is blocked, the sensor becomes unreadable, and every monitoring tool has to decide what to show you instead: a blank, a stale number, or a guess.

What actually changed

Windows ships a Vulnerable Driver Blocklist, enforced by default since Windows 11 22H2 and tightened since. WinRing0, the kernel driver behind a large share of fan and sensor utilities, is on it, because of a publicly documented vulnerability (CVE-2020-14979). In March 2025, Microsoft Defender began actively flagging it, and many people watched their fan-control and monitoring tools break overnight. Through 2026, Microsoft has continued extending these protections and is phasing out trust for older cross-signed kernel drivers entirely.

This only goes one way: unsigned or vulnerable kernel drivers are leaving the platform. That is a good thing for security, and an awkward thing for hardware monitoring.

"Have you tried running it as administrator?"

It won't help, and it's worth understanding why: administrator is a user-mode privilege level. Die-temperature sensors sit behind hardware interfaces that only kernel-mode code can touch. No amount of user-mode privilege crosses that boundary: the bottleneck is the kernel driver, not your account.

What can still be read without a kernel driver

Plenty: per-core CPU usage and clocks, memory, storage activity and drive health (including NVMe SMART and drive temperatures), network throughput, GPU identity and usage, battery health. Some ACPI thermal zones are also readable, but those measure chassis or board zones, not the die, and a tool that labels one "CPU temperature" is mislabelling it.

Tools that still read die temperature legitimately do it through a signed, Microsoft-attested kernel driver, their own or a shared one, and since 2025 more of them do. What separates them is what the driver may touch. Aikonic's is read-only, limited to an allow-list of thermal, power and fan registers, accepts no loadable modules, and reports a refused read as unavailable, with the reason, rather than replacing it with a number. A driver that can also write to hardware is a different risk, whoever signed it.

What an honest reading looks like

When a sensor can't be read, Aikonic says so, with the reason: it will tell you a value is unavailable because of Windows driver policy rather than inventing a plausible-looking number or quietly showing a board zone as your CPU die. The same rule applies everywhere, and the full argument lives on the principles page: a fan header your motherboard controls shows "auto (BIOS)" instead of a fabricated duty figure.

Aikonic ships its own small, read-only, attested driver, built to restore die temperature through Microsoft's driver attestation review, EV-signed like every binary we ship, with its threat model available to security reviewers on request. Clarity reads live CPU die temperature through it, shows what's readable on your machine, and explains every gap in one click.

Status, September 2026

What Aikonic has shipped against the problem this page describes, by public build:

• 1.1.5 (25 August): Aikonic's own sensor driver, read-only and attested; live CPU die temperature and package power on Intel.
• 1.1.8 (27 August): one driver only. Anything an earlier version registered, WinRing0 included, is removed on first run.
• 1.1.9 (1 September): a reading taken from a fallback sensor is marked as such, with the reason, so a board zone is never presented as the die.
• 1.1.10 (6 September): CPU and GPU temperatures in the system tray; AMD machines read die temperature and package power through the driver instead of the coarse Windows thermal zone.

The roadmap carries the full notes for each build, and Security describes the driver's scope and how every binary is signed.

Practical checklist

If a tool shows no CPU temperature on Windows 11 24H2 or later: it is most likely the driver situation described above, not your hardware. Your BIOS/UEFI still shows die temperature directly (it doesn't go through Windows), which is a quick way to confirm the sensor itself is fine. Be wary of any tool that suddenly shows a temperature no other tool can see. Ask it where the number comes from; if it can't tell you, it's a guess.