CVE-2026-27971 is a CVSS 9.8 unauthenticated remote code execution flaw in Qwik’s server$ RPC mechanism affecting all versions through 1.19.0, confirmed in both CISA KEV and VulnCheck KEV with active exploitation. The vulnerability requires a single HTTP request to achieve full server compromise via unsafe deserialization of attacker-controlled input in Node.js environments. Organizations running server-side Qwik must upgrade to 1.19.1 immediately or apply WAF mitigations targeting server$ RPC endpoints as a bridge control.