CVE-2026-27971 in qwik
Summary
by MITRE • 03/04/2026
Qwik is a performance focused javascript framework. qwik <=1.19.0 is vulnerable to RCE due to an unsafe deserialization vulnerability in the server$ RPC mechanism that allows any unauthenticated user to execute arbitrary code on the server with a single HTTP request. Affects any deployment where require() is available at runtime. This vulnerability is fixed in 1.19.1.
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Analysis
by VulDB Data Team • 03/06/2026
The vulnerability CVE-2026-27971 represents a critical remote code execution flaw in the Qwik JavaScript framework affecting versions 1.19.0 and earlier. This security issue stems from an unsafe deserialization vulnerability within the server$ RPC (Remote Procedure Call) mechanism that forms a core part of Qwik's server-side functionality. The flaw allows any unauthenticated attacker to execute arbitrary code on the affected server with a single HTTP request, making it particularly dangerous for web applications that rely on this framework for server-side rendering and component hydration. The vulnerability specifically impacts deployments where the require() function is available at runtime, which is common in Node.js environments where Qwik applications typically operate.
The technical exploitation of this vulnerability occurs through the server$ RPC mechanism which is designed to enable server-side functions to be called from client-side code. When the framework processes incoming RPC requests, it fails to properly validate and sanitize the serialized data passed through these mechanisms. This unsafe deserialization allows attackers to inject malicious payloads that get executed within the server context, potentially leading to complete system compromise. The vulnerability is classified under CWE-502 as Unsafe Deserialization, which is a well-known pattern that has been exploited in numerous other frameworks and applications. The attack vector requires only a single HTTP request to the vulnerable endpoint, making it highly practical for automated exploitation and increasing the potential for widespread impact.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise and data breach scenarios. An attacker who successfully exploits this vulnerability gains the same privileges as the application server, potentially allowing them to access sensitive data, modify application behavior, install backdoors, or use the compromised server as a launch point for further attacks within the network. The fact that no authentication is required makes this particularly dangerous for publicly accessible web applications or those deployed in environments where network segmentation is not properly implemented. This vulnerability directly aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) as it leverages the server's execution capabilities to run arbitrary commands.
Organizations using Qwik framework versions 1.19.0 or earlier should immediately upgrade to version 1.19.1 or later to remediate this vulnerability. The fix implemented in version 1.19.1 addresses the unsafe deserialization issue by properly validating and sanitizing all data passed through the server$ RPC mechanism. Additional mitigations include implementing network-level restrictions to limit access to server endpoints, monitoring for unusual patterns in RPC request processing, and ensuring that the require() function is not available in production environments where it is not strictly necessary. Security teams should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts, as the vulnerability's single-request nature makes it particularly susceptible to automated scanning and exploitation tools.