speedfan.sys
SpeedFan fan-control and monitoring driver (legacy)
speedfan.sys is the kernel driver for SpeedFan, the classic free fan-speed and temperature utility by Alfredo Milani Comparetti ('Almico') that was a staple of enthusiast PCs through the 2000s. The driver reads hardware-monitor chips and model-specific registers so the tool can show temperatures and drive fan speeds. SpeedFan is old and effectively unmaintained.
It is on the public record for CVE-2007-5633: the driver in SpeedFan 4.33 let a local user read and write arbitrary model-specific registers, escalate privileges, and load unsigned drivers. The flaw is ancient and well documented, and its long-known kernel primitive is most of why the file still appears on vulnerable-driver lists.
On a modern PC there is little reason to keep speedfan.sys installed. If you want fan and temperature control today, a maintained utility is the better choice, and removing the legacy SpeedFan install takes its 2007-era driver flaw with it.
speedfan.sys is listed as a known-vulnerable driver on the public LOLDrivers project. One distinct binary hash matching this filename is on record.
Status data comes from the public LOLDrivers project, a community-curated registry of drivers known to be vulnerable or malicious. The snapshot Vera uses was refreshed July 10, 2026. CVE links go to the NIST National Vulnerability Database.
Vera Project. “speedfan.sys.” Vera Field Guide (Driver). The Vera Project. https://www.veraproject.xyz/field-guide/drivers/speedfan-sys