CVE-2021-4209 · cross-distro fix matrix

CVE-2021-4209: A NULL pointer dereference flaw was found in GnuTLS. As Nettle's hash update functions internally call memcpy, providing zero-length input may cause undefined behavior. This flaw leads to a denial of service after authentication in rare circumstances.

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

Fix per ecosystem

Each block below is a distro release where CVE-2021-4209 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

gnutls28→ fixed in3.7.1-5+deb11u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y gnutls28
```

Debian bookworm

Source: Debian Security Tracker

gnutls28→ fixed in3.7.3-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y gnutls28
```

Debian trixie

Source: Debian Security Tracker

gnutls28→ fixed in3.7.3-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y gnutls28
```

Are YOU affected by CVE-2021-4209?

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

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