CVE-2021-43538 · cross-distro fix matrix

CVE-2021-43538: By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for spoofing attacks. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox

Affects 8 Linux releases across 23 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2021-43538 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

firefox-esr→ fixed in91.4.1esr-1~deb11u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y firefox-esr
```
thunderbird→ fixed in1:91.4.1-1~deb11u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y thunderbird
```

Debian bookworm

Source: Debian Security Tracker

firefox-esr→ fixed in91.4.0esr-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y firefox-esr
```
thunderbird→ fixed in1:91.4.0-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y thunderbird
```

Debian trixie

Source: Debian Security Tracker

firefox-esr→ fixed in91.4.0esr-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y firefox-esr
```
thunderbird→ fixed in1:91.4.0-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y thunderbird
```

Alpine v3.20

Source: Alpine secdb

firefox-esr→ fixed in91.4.0-r0

apk update && apk add --upgrade firefox-esr

firefox→ fixed in95.0-r0
```
apk update && apk add --upgrade firefox
```

thunderbird→ fixed in91.4.0-r0

apk update && apk add --upgrade thunderbird

Alpine v3.21

Source: Alpine secdb

firefox-esr→ fixed in91.4.0-r0

apk update && apk add --upgrade firefox-esr

firefox→ fixed in95.0-r0
```
apk update && apk add --upgrade firefox
```

librewolf→ fixed in95.0-r0

apk update && apk add --upgrade librewolf

thunderbird→ fixed in91.4.0-r0

apk update && apk add --upgrade thunderbird

Alpine edge

Source: Alpine secdb

firefox-esr→ fixed in91.4.0-r0

apk update && apk add --upgrade firefox-esr

firefox→ fixed in95.0-r0
```
apk update && apk add --upgrade firefox
```

librewolf→ fixed in95.0-r0

apk update && apk add --upgrade librewolf

thunderbird→ fixed in91.4.0-r0

apk update && apk add --upgrade thunderbird

Alpine v3.18

Source: Alpine secdb

firefox-esr→ fixed in91.4.0-r0

apk update && apk add --upgrade firefox-esr

firefox→ fixed in95.0-r0
```
apk update && apk add --upgrade firefox
```

thunderbird→ fixed in91.4.0-r0

apk update && apk add --upgrade thunderbird

Alpine v3.19

Source: Alpine secdb

firefox-esr→ fixed in91.4.0-r0

apk update && apk add --upgrade firefox-esr

firefox→ fixed in95.0-r0
```
apk update && apk add --upgrade firefox
```

thunderbird→ fixed in91.4.0-r0

apk update && apk add --upgrade thunderbird

Are YOU affected by CVE-2021-43538?

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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