CVE-2026-79319 in Stencil Core
Summary
by MITRE • 09/21/2026
Stencil core 4.43.5 is vulnerable to Incorrect Access Control.
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Analysis
by VulDB Data Team • 09/21/2026
The vulnerability identified in Stencil Core version 4.43.5 represents a critical failure in the framework's access control mechanisms, specifically categorized under CWE-284 Improper Access Control. This flaw allows unauthorized actors to interact with internal components or APIs that are intended to be restricted to authenticated users or specific system processes. In modern web development frameworks like Stencil Core, which compiles TypeScript into efficient custom elements and web components, the integrity of component initialization and lifecycle hooks is paramount for maintaining application security. When access control logic is flawed within these core utilities, it creates a pathway for attackers to bypass intended restrictions on data retrieval or state modification.
From a technical perspective, this vulnerability likely stems from insufficient validation checks during the execution of internal methods that handle resource allocation or component registration. An attacker could exploit this by crafting specific requests or injecting malicious payloads into input fields that trigger these unprotected code paths. By manipulating the parameters passed to these functions, an adversary can potentially access sensitive application data, modify user-specific states without proper authorization, or execute administrative operations intended only for privileged accounts. This type of flaw is particularly dangerous because it often bypasses standard authentication layers by exploiting logic errors rather than breaking encryption or network protocols directly.
The operational impact of this vulnerability extends beyond simple unauthorized access. It can lead to a complete compromise of the application's confidentiality and integrity. Attackers may use this entry point for further exploitation, such as Cross-Site Scripting if the vulnerable function reflects input without proper sanitization, or Server-Side Request Forgery if it allows arbitrary network requests from the backend services interacting with the frontend components. In environments where Stencil Core is used to build complex single-page applications or micro-frontends, this weakness can serve as a pivot point for lateral movement within the application architecture, potentially exposing downstream database credentials or internal service endpoints that are not directly exposed to the public internet but are accessible through compromised client-side logic.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. The primary remediation is to upgrade Stencil Core to a version where this access control issue has been resolved by the development team, ensuring that all internal APIs enforce strict role-based or attribute-based access controls as per industry best practices. Additionally, developers should implement defense-in-depth measures such as rigorous input validation and output encoding on any data passed through component props or state management systems. Integrating automated security testing tools into the continuous integration pipeline can help detect similar logic flaws early in the development lifecycle. Furthermore, adhering to OWASP guidelines for securing web applications and regularly auditing code for improper access control patterns will significantly reduce the risk of exploitation. This vulnerability aligns with ATT&CK techniques related to privilege escalation and unauthorized access, highlighting the need for robust security controls at every layer of the application stack.