CVE-2026-6766 · cross-distro fix matrix

CVE-2026-6766: Incorrect boundary conditions in the Libraries component in NSS. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

Affects 3 Linux releases across 6 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2026-6766 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

firefox-esr→ fixed in140.10.0esr-1~deb11u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y firefox-esr
```
thunderbird→ fixed in1:140.10.0esr-1~deb11u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y thunderbird
```

Debian bookworm

Source: Debian Security Tracker

firefox-esr→ fixed in140.10.0esr-1~deb12u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y firefox-esr
```
thunderbird→ fixed in1:140.10.0esr-1~deb12u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y thunderbird
```

Debian trixie

Source: Debian Security Tracker

firefox-esr→ fixed in140.10.0esr-1~deb13u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y firefox-esr
```
thunderbird→ fixed in1:140.10.0esr-1~deb13u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y thunderbird
```

Are YOU affected by CVE-2026-6766?

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-2026-6766dropped 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)