Ubuntu USN · USN-8190-1

Rack::Session vulnerability

Published: Mon, 20 Apr 2026 15:18

CVE-2026-39324

Summary

Rack::Session could allow unintended access to network services.

Details

SeungMyung Lee discovered that Rack::Session did not properly reject cookies upon decryption failure. A remote attacker could use this issue to manipulate session contents and possibly gain unauthorized access.

Recommended actions per Ubuntu release

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

Ubuntu questing

ruby-rack-session→2.1.1-0.1ubuntu0.1apt_upgrade
Standard apt upgrade. Install 2.1.1-0.1ubuntu0.1 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby-rack-session
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
ruby-rack-session→2.1.1-0.1ubuntu0.1apt_upgrade
Standard apt upgrade. Install 2.1.1-0.1ubuntu0.1 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y ruby-rack-session
```
Most apt upgrades restart their service automatically. needrestart lists anything else.

Are YOU affected by USN-8190-1?

5-second check on your actual server. Reads /etc/os-release, uname -r, and dpkg-query; matches against the live USN + Debian Security Tracker feeds; tells you whether USN-8190-1 (and any other live CVE) applies. Anonymous, no signup.

curl https://mindsparkstack.com/scan.sh | bash

Form-based quickscan Read the bash source first

Want this automated for your servers?

StackPatch runs this match against YOUR installed packages every hour

Free 1-server / $99 lifetime founder seat (50 only) / $19+/mo monthly. Indie pricing.

Buy lifetime →See StackPatch →Live audit log →