CVE-2021-3618 · cross-distro fix matrix

CVE-2021-3618: ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from

Affects 8 Linux releases across 11 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2021-3618 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

nginx→ fixed in1.18.0-6.1+deb11u2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y nginx
```

Debian bookworm

Source: Debian Security Tracker

nginx→ fixed in1.20.2-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y nginx
```
sendmail→ fixed in8.16.1-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y sendmail
```

Debian trixie

Source: Debian Security Tracker

nginx→ fixed in1.20.2-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y nginx
```
sendmail→ fixed in8.16.1-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y sendmail
```
vsftpd→ fixed in3.0.5-0.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y vsftpd
```

Alpine v3.20

Source: Alpine secdb

nginx→ fixed in1.20.1-r1
```
apk update && apk add --upgrade nginx
```

Alpine v3.21

Source: Alpine secdb

nginx→ fixed in1.20.1-r1
```
apk update && apk add --upgrade nginx
```

Alpine edge

Source: Alpine secdb

nginx→ fixed in1.20.1-r1
```
apk update && apk add --upgrade nginx
```

Alpine v3.18

Source: Alpine secdb

nginx→ fixed in1.20.1-r1
```
apk update && apk add --upgrade nginx
```

Alpine v3.19

Source: Alpine secdb

nginx→ fixed in1.20.1-r1
```
apk update && apk add --upgrade nginx
```

Are YOU affected by CVE-2021-3618?

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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