Qubes Security Bulletin 112 addresses a vulnerability known as Floating Point Divider State Sampling (XSA-488 or CVE-2025-54505) that affects older AMD processors based on the Zen or Zen Plus microarchitectures, allowing potential data inference from isolated virtual environments. Users of Qubes 4.2 and 4.3 can install security updates through the regular update interface once the packages are available in the stable repository, with a full system restart required for changes to take effect. Additionally, users employing Anti Evil Maid will need to reseal their passphrases due to changes in PCR values following the updates. This vulnerability does not impact newer AMD processors or CPUs from other manufacturers

Floating Point Divider State Sampling update for Qubes OS

Qubes Security Bulletin 112 addresses the Floating Point Divider State Sampling vulnerability, also tracked as XSA-488 or CVE-2025-54505, which could let attackers infer data from isolated virtual environments. The flaw specifically targets older AMD processors built on the Zen or Zen Plus microarchitecture, while newer chips and competing brands remain unaffected. Once the packages reach the stable repository, Qubes 4.2 and 4.3 users can install them via the regular update interface. A full system restart is required for the changes to take effect, and Anti Evil Maid owners must also reseal their passphrases since PCR values will shift.

QSB-112: Floating Point Divider State Sampling (XSA-488)

Floating Point Divider State Sampling update for Qubes OS @ Linux Compatible