The vulnerability stems from how ingress-nginx constructs filenames for basic auth secrets. The system combines namespace and secret names to create file paths without sufficient sanitization. When either contains hyphens, an attacker can craft malicious namespace/secret combinations that resolve to the same file path as another ingress' auth file. The createAuthFile function (or equivalent) would be directly responsible for this insecure path construction, matching CWE-73 (path control) and CWE-610 (cross-sphere reference). While exact code isn't available, the vulnerability pattern and ingress-nginx architecture strongly indicate this as the vulnerable component.