CVE-2018-18955 · cross-distro fix matrix

CVE-2018-18955: In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resour

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

Fix per ecosystem

Each block below is a distro release where CVE-2018-18955 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

linux→ fixed in4.18.20-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y linux
```

Debian bookworm

Source: Debian Security Tracker

linux→ fixed in4.18.20-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y linux
```

Debian trixie

Source: Debian Security Tracker

linux→ fixed in4.18.20-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y linux
```

Are YOU affected by CVE-2018-18955?

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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