CVE-2026-115750 in mcp-from-openapi
Summary
by MITRE • 10/23/2026
mcp-from-openapi from 2.5.0 before 2.9.0 contains a credential exposure vulnerability that allows attackers to capture Authorization and Cookie headers because safeFetch() forwards them on cross-origin redirects. Attackers controlling a spec host or abusing an open redirect can redirect fromURL() spec requests to their own origin to steal bearer tokens or cookies.
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Analysis
by VulDB Data Team • 10/24/2026
The mcp-from-openapi library, specifically in versions prior to 2.9.0, contains a critical credential exposure vulnerability rooted in improper handling of HTTP redirects during cross-origin requests. This flaw arises from the implementation of the safeFetch function, which is designed to manage network requests for OpenAPI specifications but fails to strip sensitive authentication headers when following redirections across different origins. When an application utilizes this library to fetch resources defined by a remote specification file, it may inadvertently transmit Authorization and Cookie headers along with the initial request if those credentials are required for accessing the original resource or related services. The vulnerability is triggered specifically during cross-origin redirects, where the browser's default behavior or the underlying HTTP client logic preserves these sensitive headers unless explicitly instructed otherwise, creating an opportunity for malicious actors to intercept them.
The operational impact of this vulnerability allows attackers who control a spec host or can exploit an open redirect within the target application to steal bearer tokens and session cookies. By manipulating the URL referenced in the OpenAPI specification, an attacker can configure the endpoint to return a HTTP 3xx response that redirects the request to a domain under their control. Because safeFetch forwards the Authorization and Cookie headers on these cross-origin redirects, the malicious server receives full access to the victim's authentication credentials. This compromise enables session hijacking, unauthorized access to protected resources, and potential privilege escalation within the affected application ecosystem. The severity is heightened by the fact that OpenAPI specifications are often fetched dynamically from external sources or user-provided inputs, increasing the attack surface for such redirection-based attacks.
This vulnerability aligns with CWE-524, which categorizes exposure of sensitive information to an unauthorized actor through improper handling during redirects. From a tactical perspective, it maps to ATT&CK technique T1078, Valid Accounts, as stolen credentials can be used to impersonate legitimate users. It also relates to T1539, Steal Web Session Cookie, and potentially T1048, Exfiltration Over Alternative Protocol if the attacker uses non-standard channels for data exfiltration after capturing the headers. The core issue lies in the lack of strict origin validation or header stripping logic when transitioning between different security contexts during HTTP redirections, violating the principle of least privilege regarding credential transmission across domains.
To mitigate this vulnerability, organizations should immediately upgrade mcp-from-openapi to version 2.9.0 or later, where the safeFetch function has been patched to prevent forwarding sensitive headers on cross-origin redirects. For applications unable to update promptly, implementing a custom fetch wrapper that explicitly clears Authorization and Cookie headers before following any redirect is recommended. Additionally, developers should enforce strict Content Security Policy directives to limit unauthorized data exfiltration channels and validate all external URLs referenced in OpenAPI specifications against an allowlist of trusted domains. Regular security audits focusing on HTTP client configurations and redirect handling logic are essential to prevent similar credential leakage scenarios in other parts of the application stack.