CVE Catalog

CVE-2026-91768

MediumCVSS 6.5
Published: Translated: NVD NIST

Summary

The IPv6 branch of the FastCGI client access check compares only the first 12 bytes of a 16-byte IPv6 address, so listen.allowed_clients matches on a /96 prefix instead of the exact address. An attacker who can source an address sharing the first 96 bits with an allowed one passes the check and reaches the FastCGI endpoint.

Risk Assessment

The risk includes unauthorized access to FastCGI endpoints, potentially allowing an attacker to perform unauthorized operations or access sensitive resources.

Recommendation

It is recommended to update the component to a patched version that compares full 16-byte IPv6 addresses.

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Original NVD description (English source)

The IPv6 branch of the FastCGI client access check compares only the first 12 bytes of a 16-byte IPv6 address, so listen.allowed_clients matches on a /96 prefix instead of the exact address. An attacker who can source an address sharing the first 96 bits with an allowed one passes the check and reaches the FastCGI endpoint.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS