FHN 
Angular XSS vulnerability in i18n handling exposes web applications to script injection when unsafe attributes are improperly bound.
This issue exists in core Angular components and can allow attackers to inject malicious scripts if applications are not properly handling user input.
The problem occurs when developers use i18n with sensitive attributes like links or resource paths. Normally, Angular protects applications by sanitizing input, but in this case, that protection can be bypassed. If untrusted data is directly bound to these attributes, attackers can execute scripts within the application context.
Commonly affected attributes include href, src, action, background, data, and formaction. Applications running versions between 17.x and early 22.x releases are particularly at risk, especially if they rely on user-controlled data in these areas.
Impact and Mitigation
Successful exploitation allows attackers to run malicious scripts inside a user’s browser session, which can lead to serious security issues such as:
- Session hijacking through stolen cookies or tokens
- Extraction of sensitive user data
- Performing actions on behalf of users without consent
Angular has released fixes in newer versions, and upgrading to patched releases is the most effective solution. However, older versions (like 17 and 18) still require additional precautions.
To reduce risk, teams should follow these key practices:
- Avoid binding untrusted user input directly to sensitive HTML attributes
- Do not combine i18n with attributes that handle URLs or actions
- Apply manual sanitization using Angular’s security utilities before rendering data
Overall, this vulnerability highlights how small configuration changes can weaken built-in protections, making secure coding practices and timely updates critical for Angular applications.
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