CVE-2021-20247 · cross-distro fix matrix

CVE-2021-20247: A flaw was found in mbsync before v1.3.5 and v1.4.1. Validations of the mailbox names returned by IMAP LIST/LSUB do not occur allowing a malicious or compromised server to use specially crafted mailbox names containing '..' path components to access data outside the designated mailbox on the opposit

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

Fix per ecosystem

Each block below is a distro release where CVE-2021-20247 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

isync→ fixed in1.3.0-2.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y isync
```

Debian bookworm

Source: Debian Security Tracker

isync→ fixed in1.3.0-2.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y isync
```

Debian trixie

Source: Debian Security Tracker

isync→ fixed in1.3.0-2.1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y isync
```

Alpine v3.20

Source: Alpine secdb

isync→ fixed in1.4.1-r0
```
apk update && apk add --upgrade isync
```

Alpine v3.21

Source: Alpine secdb

isync→ fixed in1.4.1-r0
```
apk update && apk add --upgrade isync
```

Alpine edge

Source: Alpine secdb

isync→ fixed in1.4.1-r0
```
apk update && apk add --upgrade isync
```

Alpine v3.18

Source: Alpine secdb

isync→ fixed in1.4.1-r0
```
apk update && apk add --upgrade isync
```

Alpine v3.19

Source: Alpine secdb

isync→ fixed in1.4.1-r0
```
apk update && apk add --upgrade isync
```

Are YOU affected by CVE-2021-20247?

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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