Race Condition Vulnerability in Ruby 4 Affecting DNS Response Handling

CVE-2026-46727

What is CVE-2026-46727?

CVE-2026-46727 is a vulnerability identified in Ruby 4, specifically affecting versions prior to 4.0.5. This flaw is characterized as a race condition within the pthread-based timeout handler utilized by the Addrinfo and Socket classes for handling DNS responses. When an attack exploits this vulnerability, it can lead to a use-after-free condition, potentially resulting in a crash of the Ruby process involved. This scenario occurs when a remote attacker manages to introduce a delay in DNS responses close to the user-defined timeout settings. The implications of this vulnerability are significant for organizations relying on Ruby for their applications, as interruptions can lead to degraded performance and system instability. In a managed environment, failure in DNS resolution could hamper critical functionalities of web services and applications, creating a deterrent for user experience.

Potential impact of CVE-2026-46727

1. System Crashes: Exploiting this vulnerability can lead to the crashing of Ruby processes during DNS resolution, causing temporary denial of service and disruption of applications that depend on these processes.

2. Memory Corruption Risks: Although direct exploitation is not confirmed, the presence of a use-after-free condition suggests theoretical opportunities for memory corruption attacks, which could be leveraged for gaining unauthorized access or control over impacted systems.

3. Operational Disruption: Organizations that rely on Ruby for backend services may face operational interruptions. Denial of service resulting from this vulnerability can affect user access and application availability, leading to potential financial losses and damage to reputation.

References