CVE-2015-8555 · cross-distro fix matrix

CVE-2015-8555: Xen 4.6.x, 4.5.x, 4.4.x, 4.3.x, and earlier do not initialize x86 FPU stack and XMM registers when XSAVE/XRSTOR are not used to manage guest extended register state, which allows local guest domains to obtain sensitive information from other domains via unspecified vectors.

Affects 3 Linux releases across 3 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2015-8555 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

xen→ fixed in4.8.0~rc3-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y xen
```

Debian bookworm

Source: Debian Security Tracker

xen→ fixed in4.8.0~rc3-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y xen
```

Debian trixie

Source: Debian Security Tracker

xen→ fixed in4.8.0~rc3-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y xen
```

Are YOU affected by CVE-2015-8555?

5-second check on your actual server. Reads /etc/os-release, uname -r, and the distro's package manager; matches against this same cross-source index live.

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