CVE-2026-67435 in monitoring-plugins
Summary
by MITRE • 07/29/2026
linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations. Prior to version 6.0.0, lib.url.fetch() followed cross-origin redirects while forwarding caller-supplied credential headers other than Authorization and Cookie, allowing a malicious redirect-capable server to receive headers such as X-Auth-Token from authenticated monitoring requests. This issue is fixed in version 6.0.0.
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Analysis
by VulDB Data Team • 07/29/2026
The vulnerability in linuxfabrik-lib affects the lib.url.fetch() function prior to version 6.0.0, creating a significant security risk through improper handling of cross-origin redirects. This flaw represents a classic case of information disclosure via unauthorized header forwarding during HTTP redirect operations. The technical implementation fails to properly sanitize or restrict credential headers when following redirects to external domains, allowing malicious servers to intercept sensitive authentication tokens and session identifiers.
The vulnerability specifically impacts how the library handles HTTP redirect responses that point to different origins or domains. When a request is made through lib.url.fetch() and encounters a redirect response, the function continues processing but forwards certain caller-supplied credential headers beyond the original domain boundary. While Authorization and Cookie headers are properly excluded from forwarding, other authentication-related headers such as X-Auth-Token are not adequately filtered, creating an attack surface where malicious actors can exploit redirect capabilities to capture these tokens.
This issue enables a malicious redirect-capable server to receive sensitive authentication information from authenticated monitoring requests, potentially allowing attackers to hijack sessions or impersonate legitimate users. The flaw operates at the application layer and represents a violation of secure coding practices for cross-origin resource handling. According to CWE-201, this vulnerability falls under "Information Exposure Through Sent Data" where sensitive data is inadvertently transmitted to unauthorized parties through redirect mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, as captured authentication tokens could enable attackers to perform unauthorized actions within the monitored systems or services. An attacker with control over a malicious server could potentially intercept and utilize these tokens for further attacks, including privilege escalation or data exfiltration. The issue affects monitoring systems that rely on linuxfabrik-lib for API integrations, making it particularly concerning for security-critical infrastructure components.
Security professionals should consider this vulnerability in relation to ATT&CK technique T1566.002 "Phishing for Information" and T1071.004 "Application Layer Protocol: DNS" where redirect-based attacks can be leveraged to capture authentication tokens. The fix implemented in version 6.0.0 addresses this by introducing proper header filtering mechanisms that prevent credential headers from being forwarded during cross-origin redirects, aligning with secure redirect handling practices outlined in OWASP recommendations for HTTP security headers and cross-origin resource sharing.
Organizations using affected versions of linuxfabrik-lib should immediately upgrade to version 6.0.0 or later to mitigate the risk of credential exposure through malicious redirects. System administrators should also implement monitoring for suspicious redirect patterns and validate that authentication tokens are not being transmitted to unexpected domains during normal operations. The vulnerability highlights the importance of proper input validation and header sanitization in network communication libraries, particularly those handling authenticated requests in security monitoring contexts where sensitive information flows through automated systems.