Beego is a popular open-source web framework for the Go programming language. It provides an efficient and elegant way for developers to create web applications. Unfortunately, a Cross-Site Scripting (XSS) vulnerability has been discovered in Beego's RenderForm() function, affecting versions prior to 2.3.6. This post will delve into the details of this vulnerability, discuss the potential impact, and provide recommendations for mitigation.

Vulnerability Details

The vulnerability (CVE-2025-30223) exists in Beego's RenderForm() function. This function takes a user-provided value and generates an HTML form based on the input. However, prior to version 2.3.6, Beego does not properly escape the HTML content of user-controlled data. As a result, attackers can inject malicious JavaScript code that executes in the victims' browsers, potentially leading to session hijacking, credential theft, or account takeover.

Here's an example code snippet that demonstrates the vulnerability

package main

import (
    "github.com/astaxie/beego"
)

type HelloController struct {
    beego.Controller
}

func (c *HelloController) Get() {
    userInput := c.Ctx.Input.Param(":userInput")
    c.Data["Form"] = beego.RenderForm(userInput)
    c.TplName = "hello.tpl"
}

func main() {
    beego.Router("/hello/:userInput", &HelloController{})
    beego.Run()
}

In this example, the application takes a user-provided value through the URL and passes it to the RenderForm() function. The generated HTML form is then included in the template, making it vulnerable to XSS attacks.

Impact and Exploit Scenario

Attackers can exploit this vulnerability by crafting URLs containing malicious JavaScript code and tricking users into following these links. For example, an attacker could share a link that includes the XSS payload in a social media post or send it through email. When victims visit the link, their browsers execute the malicious JavaScript code.

This can have a severe impact on affected web applications, and may lead to the following

1. Session hijacking: Attackers can gain unauthorized access to a victim's session by stealing their session cookies. This can grant them control over the victim's account.
2. Credential theft: Attackers can steal victims' login credentials (like usernames and passwords) when victims interact with the compromised form.
3. Account takeover: Attackers can utilize the stolen session cookies or credentials to take over victims' accounts, potentially leading to unauthorized actions or data access.

Mitigation and Solution

The Beego development team has addressed this issue in the 2.3.6 release by adding proper HTML escaping for user-provided data in the RenderForm() function. All users are strongly encouraged to update their Beego version to 2.3.6 or later.

If updating is not immediately possible, developers can implement manual escaping of user-controlled data before passing it to the RenderForm() function. This can help reduce the risk of XSS attacks:

userInput := c.Ctx.Input.Param(":userInput")
escapedUserInput := template.HTMLEscapeString(userInput)
c.Data["Form"] = beego.RenderForm(escapedUserInput)

Conclusion

This post analyzed the CVE-2025-30223 XSS vulnerability in Beego's RenderForm() function. To protect your web application from this vulnerability, it is crucial to keep your Beego version up-to-date and ensure proper handling and escaping of user-controlled data. Remember that even seemingly high-level functions can introduce security risks if not used properly. By staying informed and vigilant, developers can create more secure and trustworthy applications.

Timeline

Published on: 03/31/2025 17:15:42 UTC
Last modified on: 04/01/2025 20:26:22 UTC