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TL;DR
CISA added CVE-2025-62593 to its Known Exploited Vulnerabilities catalog. The flaw is a code injection bug in Ray, a popular Python framework for scaling AI and Python workloads. It allows remote code execution against developers who run Ray locally. A public proof-of-concept exploit exists, and CISA confirms active exploitation. The fix ships in Ray 2.52.0.
- CVE: CVE-2025-62593
- CVSS: 9.4 (Critical · CVSSv4)
- Product: ray (pip)
- Affected: < 2.52.0
- Impact: Ray is vulnerable to RCE via Safari & Firefox Browsers through DNS Rebinding Attack
- Status: Exploited in the wild.
- Patched in: 2.52.0
- EPSS: 0.4% (30-day)
- Action: Update to 2.52.0 now
Why It Matters
Ray runs on the machines of many AI and Python developers. This CVE-2025-62593 remote code execution flaw turns a casual web visit into a full compromise. A developer who opens a malicious page can have shell code run on their machine.
On August 17, 2026, CISA added the flaw to its KEV catalog based on evidence of active exploitation. That listing marks a shift from theory to real-world attacks. Federal agencies must now remediate it under CISA’s binding directive.
How the Attack Works
Ray exposes job endpoints without authentication by default. Its dashboard tries to block browser traffic using a weak check. That check only tests whether the User-Agent header starts with “Mozilla.”
The assumption behind that guard is wrong. In Firefox and Safari, the fetch API lets a script change the User-Agent header. Chrome avoids the issue only due to a separate bug that puts it out of spec.
To reach the local Ray service, an attacker pairs this weakness with a DNS rebinding attack. As a result, a malicious website or a malicious ad can send commands to Ray. The official Ray security advisory for CVE-2025-62593 describes the mechanism in detail. Attackers can also pivot through the browser to hit Ray instances inside a private network. This report omits any working exploit steps.
Affected Versions
The vulnerability affects Ray versions before 2.52.0. The bug carries a CVSS score of 9.4, which places it in the critical range.
Exploitation targets developers using Firefox or Safari on systems running a local Ray dashboard, typically on port 8265. Chrome users are not affected by this specific browser vector.
Patch and Mitigation Steps
First, update Ray to version 2.52.0 or later without delay. That release also adds an optional, disabled-by-default token authentication feature for extra hardening.
Next, avoid exposing the Ray dashboard to untrusted networks. You should also enable the new authentication option where possible. Because browsers have only recently started hardening against DNS rebinding, patching remains the strongest defense. CISA requires federal agencies to remediate KEV-listed flaws by the assigned due date.
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