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CriticalVulnerabilityupdated 30 Oct 2026, 14:17 UTC

Ruby on Rails: flaw can leak sensitive information

A weakness in Ruby on Rails, a popular framework for building websites, lets an anonymous outsider pull data they should not see. That data could help them take over more of the system.

Official source
SeverityCriticalVulnerability
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official sourceBacked by an official source

What happened

A vulnerability in Ruby on Rails allows a remote, unauthenticated attacker to disclose information. The material notes it may lead to remote code execution or lateral movement.

Why it is dangerous: Attackers may gain access to internal data or use leaked details to move deeper into affected systems. Any organization running vulnerable Rails applications on internet-facing servers is at risk.

Are you affected?

You are affected if you run a vulnerable version of Ruby on Rails in an application reachable over the network.

What to do

  1. Identify all Ruby on Rails applications in your environment and their versions
  2. Check the CERT-Bund advisory for the list of affected versions and any official fix
  3. Apply the vendor's patch or update to a fixed Rails version as soon as it is available
  4. Restrict external access to affected applications until patched

Timeline

  1. 30 Oct 2026, 14:17 UTC
    Publicly disclosed
  2. 30 Oct 2026, 14:17 UTC
    Reported by CERT-Bund (BSI) · CERT-Bund (BSI)
  3. 30 Oct 2026, 14:17 UTC
    Picked up by Zero Radar

Sources 1 report, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
ZR-cb632842
Disclosed
30 Oct 2026, 14:17 UTC
On Zero Radar
30 Oct 2026, 14:17 UTC (1 min after disclosure)
Last change
30 Oct 2026, 14:17 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

Ruby on Rails: flaw can leak sensitive information · Zero Radar