Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in FrontendHandler.go

[gtqbhksl]

Cause of vulnerability: A potential Cross-site scripting (XSS) vulnerability exists on line 19 of the FrontendHandler.go file in the code. The vulnerability is caused by user-supplied values being inserted directly into the generated HTML page without proper processing or escaping. Specifically, the 'PageRenderHtmlByAlias' function takes an alias parameter and inserts it directly into the returned HTML string. If an attacker is able to control this alias parameter and inject malicious scripts, these scripts will be executed in the user's browser, resulting in a cross-site scripting attack. This situation is very dangerous because it allows an attacker to execute arbitrary code or steal user information.

FrontendHandler.go line 33-52

func (cms *Cms) FrontendHandlerRenderAsString(w http.ResponseWriter, r *http.Request) string {
    uri := r.RequestURI

    if strings.HasSuffix(uri, ".ico") {
        return ""
    }

    languageAny := r.Context().Value(LanguageKey{})
    language := utils.ToString(languageAny)

    if cms.translationsEnabled {
        isValidLanguage := lo.Contains(lo.Keys(cms.translationLanguages), language)

        if !isValidLanguage {
            language = cms.translationLanguageDefault
        }
    }

    return cms.PageRenderHtmlByAlias(r, r.URL.Path, language)
}

PageBuildHtml.go line 10-22

// PageRenderHtmlByAlias builds the HTML of a page based on its alias
func (cms *Cms) PageRenderHtmlByAlias(r *http.Request, alias string, language string) string {
    page, err := cms.PageFindByAlias(alias)

    if err != nil {
        cms.LogStore.ErrorWithContext("At pageBuldHTMLByAlias", err.Error())
        return "Page with alias '" + alias + "' not found"
    }

    if page == nil {
        return "Page with alias '" + alias + "' not found"
    }

    pageAttrs, err := page.GetAttributes()

    if err != nil {
        return "Page '" + alias + "' io exception"
    }

[lesichkovm]

Thank you @gtqbhksl . Nice catch

This has now been fixed.