teler-waf subject to bypass of common web attack threat rule with HTML entities payload

teler-waf is a Go HTTP middleware that provides teler IDS functionality to protect against web-based attacks. In teler-waf prior to version 0.1.1 is vulnerable to bypassing common web attack rules when a specific HTML entities payload is used. This vulnerability allows an attacker to execute arbitrary JavaScript code on the victim's browser and compromise the security of the web application. The vulnerability exists due to teler-waf failure to properly sanitize and filter HTML entities in user input. An attacker can exploit this vulnerability to bypass common web attack threat rules in teler-waf and launch cross-site scripting (XSS) attacks. The attacker can execute arbitrary JavaScript code on the victim's browser and steal sensitive information, such as login credentials and session tokens, or take control of the victim's browser and perform malicious actions. This issue has been fixed in version 0.1.1.

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as <, >, and & that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may obtain information outside the intended access boundary.