CVE-2021-20254 · cross-distro fix matrix

CVE-2021-20254: A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache.

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

Fix per ecosystem

Each block below is a distro release where CVE-2021-20254 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

samba→ fixed in2:4.13.5+dfsg-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y samba
```

Debian bookworm

Source: Debian Security Tracker

samba→ fixed in2:4.13.5+dfsg-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y samba
```

Debian trixie

Source: Debian Security Tracker

samba→ fixed in2:4.13.5+dfsg-2urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y samba
```

Alpine v3.20

Source: Alpine secdb

samba→ fixed in4.14.4-r0
```
apk update && apk add --upgrade samba
```

Alpine v3.21

Source: Alpine secdb

samba→ fixed in4.14.4-r0
```
apk update && apk add --upgrade samba
```

Alpine edge

Source: Alpine secdb

samba→ fixed in4.14.4-r0
```
apk update && apk add --upgrade samba
```

Alpine v3.18

Source: Alpine secdb

samba→ fixed in4.14.4-r0
```
apk update && apk add --upgrade samba
```

Alpine v3.19

Source: Alpine secdb

samba→ fixed in4.14.4-r0
```
apk update && apk add --upgrade samba
```

Are YOU affected by CVE-2021-20254?

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

CVE-2021-20254dropped silently in your distro's update channel. Every new CVE is the same story. StackPatch runs the matcher hourly against all 5 sources and emails the exact remediation when something new applies to one of your servers. $99 lifetime, 50 founder seats, 30-day refund.

See StackPatch ($99 lifetime)