Comment by fsflover

1 day ago

When was the last Flatpak escape? Last VM escape from VT-d virtualization, which Qubes uses by default, was found in 2006 by the Qubes founder, https://en.wikipedia.org/wiki/Blue_Pill_(software)

The most recent VM escape from VT-d virtualization was in 2022[0].

Escapes are not the only vulnerability. QSB-108 allows for reading the memory of other qubes running on the host[1].

[0] https://nvd.nist.gov/vuln/detail/CVE-2020-15565

[1] https://www.qubes-os.org/news/2025/07/11/qsb-108/

  • Apart from the fact that this is extremely rare, the first vulnerability is not a complete escape. For example, any offline vault VM storing secrets stayed secure. This is just not happening with any other security approach.

    Speculative sidechannel attacks have nothing to do with OS or compartmentalization technology, since they are the problem of CPUs. Nothing can help here, so this is irrelevant to this discussion. Except that Qubes Air will save you in the future: https://www.qubes-os.org/news/2018/01/22/qubes-air/

    • > Apart from the fact that this is extremely rare,

      So are bubblewrap escapes, which is the sandbox flatpak uses.

      > the first vulnerability is not a complete escape.

      It could potentially lead to one, and being able to obtain information from other VMs defeats much of the point of isolation, and so defeats much of the point of why people use qubes.

      > For example, any offline vault VM storing secrets stayed secure. This is just not happening with any other security approach.

      That's not true. Strong MAC would suffice, no VT-d needed.

      > Speculative sidechannel attacks have nothing to do with OS or compartmentalization technology

      Of course they do, in fact they have more to do with it than solutions like flatpak, which is why Qubes releases security advisories and patches to address those vulnerabilities.