Ubuntu USN · USN-8431-1

Ruby vulnerabilities

Published: Mon, 15 Jun 2026 17:24

CVE-2026-42257CVE-2026-42246

Summary

Ruby could allow unintended access to network services.

Details

It was discovered that Ruby's Net::IMAP library did not properly verify that Transport Layer Security (TLS) encryption was started after issuing a STARTTLS command. A remote attacker could possibly use this issue to perform a machine-in-the-middle attack and silently bypass TLS encryption. (CVE-2026-42246) It was also discovered that Ruby's Net::IMAP library did not validate string arguments passed to certain commands. A remote attacker could possibly use this issue to inject arbitrary IMAP commands. (CVE-2026-42257)

Recommended actions per Ubuntu release

StackPatch playbook auto-generated per release codename and per affected package.

Ubuntu bionic

ruby2.5→2.5.1-1ubuntu1.16+esm8apt_upgrade
Standard apt upgrade. Install 2.5.1-1ubuntu1.16+esm8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.5
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libruby2.5→2.5.1-1ubuntu1.16+esm8apt_upgrade
Standard apt upgrade. Install 2.5.1-1ubuntu1.16+esm8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libruby2.5
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.5→2.5.1-1ubuntu1.16+esm8apt_upgrade
Standard apt upgrade. Install 2.5.1-1ubuntu1.16+esm8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.5
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.5-dev→2.5.1-1ubuntu1.16+esm8apt_upgrade
Standard apt upgrade. Install 2.5.1-1ubuntu1.16+esm8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.5-dev
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.5-doc→2.5.1-1ubuntu1.16+esm8apt_upgrade
Standard apt upgrade. Install 2.5.1-1ubuntu1.16+esm8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.5-doc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.

Ubuntu xenial

ruby2.3→2.3.1-2~ubuntu16.04.16+esm14apt_upgrade
Standard apt upgrade. Install 2.3.1-2~ubuntu16.04.16+esm14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.3
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libruby2.3→2.3.1-2~ubuntu16.04.16+esm14apt_upgrade
Standard apt upgrade. Install 2.3.1-2~ubuntu16.04.16+esm14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libruby2.3
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.3→2.3.1-2~ubuntu16.04.16+esm14apt_upgrade
Standard apt upgrade. Install 2.3.1-2~ubuntu16.04.16+esm14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.3
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.3-dev→2.3.1-2~ubuntu16.04.16+esm14apt_upgrade
Standard apt upgrade. Install 2.3.1-2~ubuntu16.04.16+esm14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.3-dev
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.3-doc→2.3.1-2~ubuntu16.04.16+esm14apt_upgrade
Standard apt upgrade. Install 2.3.1-2~ubuntu16.04.16+esm14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.3-doc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby2.3-tcltk→2.3.1-2~ubuntu16.04.16+esm14apt_upgrade
Standard apt upgrade. Install 2.3.1-2~ubuntu16.04.16+esm14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby2.3-tcltk
```
Most apt upgrades restart their service automatically. needrestart lists anything else.

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