CVE-2021-21401 · cross-distro fix matrix

CVE-2021-21401: Nanopb is a small code-size Protocol Buffers implementation in ansi C. In Nanopb before versions 0.3.9.8 and 0.4.5, decoding a specifically formed message can cause invalid `free()` or `realloc()` calls if the message type contains an `oneof` field, and the `oneof` directly contains both a pointer f

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

Fix per ecosystem

Each block below is a distro release where CVE-2021-21401 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

nanopb→ fixed in0.4.4-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y nanopb
```

Debian bookworm

Source: Debian Security Tracker

nanopb→ fixed in0.4.4-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y nanopb
```

Debian trixie

Source: Debian Security Tracker

nanopb→ fixed in0.4.4-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y nanopb
```

Are YOU affected by CVE-2021-21401?

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.

curl https://mindsparkstack.com/scan.sh | bash

Form-based quickscan View on NVD

Continuous monitoring beats manual checking

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