False negative in java/unvalidated-url-redirection for Spring MVC redirect view names

まず、安定版の java/unvalidated-url-redirection クエリと実験版の java/spring-unvalidated-url-redirection クエリを比較し、Spring のリダイレクトビュー名とヘルパーを介したフローに焦点を当てます。redirect:、ModelAndView、RedirectView の形式を含む、一覧に記載されたパターンを再現し、ユーザーが制御するターゲットが報告される一方で、安全なリダイレクトには影響がないことを確認します。

I ran into a false negative in the Java URL redirection queries for a common Spring MVC pattern.

java/unvalidated-url-redirection does not appear to cover redirects expressed through Spring view names like return "redirect:" + userControlledValue, especially when that construction is wrapped in a helper method.

I found this on a public CVE, CVE-2025-8813, in atjiu/pybbs.

Vulnerable code:

@GetMapping("changeLanguage")
public String changeLanguage(String lang, HttpSession session, HttpServletRequest request) {
    String referer = request.getHeader("referer");
    if ("zh".equals(lang)) {
        session.setAttribute(SessionLocaleResolver.LOCALE_SESSION_ATTRIBUTE_NAME, Locale.SIMPLIFIED_CHINESE);
    } else if ("en".equals(lang)) {
        session.setAttribute(SessionLocaleResolver.LOCALE_SESSION_ATTRIBUTE_NAME, Locale.US);
    }
    return StringUtils.isEmpty(referer) ? redirect("/") : redirect(referer);
}

protected String redirect(String path) {
    return "redirect:" + path;
}

This was fixed upstream by removing the user-controlled redirect target:
https://github.com/atjiu/pybbs/commit/edb14ff13e9e05394960ba46c3d31d844ff2deac

My understanding is that the stable query covers servlet-style redirect sinks such as sendRedirect(...) and Location headers, but not the Spring MVC redirect-by-view-name sink family. In this case the source is straightforward (request.getHeader("referer")) and the flow is short, so the gap seems to be sink coverage rather than source modeling.

This pattern is common in practice:

• return "redirect:" + next
• return new ModelAndView("redirect:" + next)
• return new RedirectView(next)
• helper wrappers such as redirect(next) in a base controller or utility class

That last form is especially common in real Spring code, so this is not just a one-off CVE shape. I would expect similar misses whenever a project centralizes redirect construction in a helper.

There is already an experimental query, java/spring-unvalidated-url-redirection, so this may just be a case where the relevant Spring sink modeling has not made it into the stable query set yet.

A reasonable fix might be to bring the Spring redirect sink coverage into the stable rule family, especially for:

• "redirect:" + tainted
• new ModelAndView("redirect:" + tainted)
• new RedirectView(tainted)
• helper-mediated variants that ultimately construct a Spring redirect view name