CISA Adds Critical Ray RCE Flaw to KEV Catalog Amid Active Exploitation

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added a critical remote code execution vulnerability in Ray, tracked as CVE-2025-62593 with a CVSS score of 9.4, to its Known Exploited Vulnerabilities (KEV) catalog. Ray is a Python-native distributed computing framework widely used to scale artificial intelligence and machine learning workloads, with more than 43,500 stars on GitHub and over 7,900 forks. The flaw stems from the Ray development team's longstanding decision not to implement authentication on critical endpoints such as /api/jobs and /api/job_agent/jobs/, allowing attackers to execute arbitrary code in development contexts.

The vulnerability is exploitable through a DNS rebinding attack when combined with manipulated User-Agent headers in browsers like Mozilla Firefox and Apple Safari. According to Ray maintainers, a developer running Ray who inadvertently visits a malicious website or is served a malicious advertisement could have arbitrary shell code executed on their machine. The issue, fixed in Ray version 2.52.0, primarily impacts developers running development and testing environments. Security teams can use a DNS leak test to validate DNS resolution hardening and a port scanner to identify any exposed Ray dashboard endpoints on their network perimeter.

Threat actors have already weaponized the flaw at scale. A BitSight report from March 2026 revealed that operators behind the RondoDox DDoS botnet incorporated the vulnerability into their arsenal just two days after a proof-of-concept was publicly disclosed on November 26, 2025. Separately, Oligo Security researchers have documented ShadowRay 2.0, a campaign targeting unpatched Ray instances equipped with NVIDIA GPUs to build a self-replicating cryptocurrency mining botnet. The attack can also pivot to network-adjacent Ray instances inside private corporate networks by leveraging the victim's browser as a confused deputy intermediary.

Ray maintainers credited Oligo Security researcher Avi Lumelsky for discovering the fetch bypass and Jonathan Leitschuh for the DNS rebinding technique. While CISA has not disclosed specific in-the-wild exploitation details, Federal Civilian Executive Branch (FCEB) agencies are required to apply patches immediately and audit their environments for indicators of compromise. Organizations running Ray clusters should verify installations are upgraded to version 2.52.0 or later and conduct a thorough privacy checkup to confirm no internal services are inadvertently exposed to browser-based threats.