CVE-2026-42257 · cross-distro fix matrix

CVE-2026-42257: It was discovered that Ruby's Net::IMAP library did not properly verify

Affects 2 Linux releases across 9 (distro × package) combinations. First disclosed: 2026-05-09.

Fix per ecosystem

Each block below is a distro release where CVE-2026-42257 has a known fix. Run the listed command on that distro to remediate.

Ubuntu bionic

Source: Ubuntu USN

ruby2.5→ fixed in2.5.1-1ubuntu1.16+esm8USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.5
```
libruby2.5→ fixed in2.5.1-1ubuntu1.16+esm8USN-8431-1
```
sudo apt-get install --only-upgrade -y libruby2.5
```
ruby2.5-dev→ fixed in2.5.1-1ubuntu1.16+esm8USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.5-dev
```
ruby2.5-doc→ fixed in2.5.1-1ubuntu1.16+esm8USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.5-doc
```

Ubuntu xenial

Source: Ubuntu USN

ruby2.3→ fixed in2.3.1-2~ubuntu16.04.16+esm14USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.3
```
libruby2.3→ fixed in2.3.1-2~ubuntu16.04.16+esm14USN-8431-1
```
sudo apt-get install --only-upgrade -y libruby2.3
```
ruby2.3-dev→ fixed in2.3.1-2~ubuntu16.04.16+esm14USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.3-dev
```
ruby2.3-doc→ fixed in2.3.1-2~ubuntu16.04.16+esm14USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.3-doc
```
ruby2.3-tcltk→ fixed in2.3.1-2~ubuntu16.04.16+esm14USN-8431-1
```
sudo apt-get install --only-upgrade -y ruby2.3-tcltk
```

Are YOU affected by CVE-2026-42257?

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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Continuous monitoring beats manual checking

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