WeKnora is an LLM-powered framework designed for deep document understanding and semantic retrieval. Prior to version 0.3.0, a DNS rebinding vulnerability in the web_fetch tool allows an unauthenticated attacker to bypass URL validation and access internal resources on the server, including private IP addresses (e.g., 127.0.0.1, 192.168.x.x). By crafting a malicious domain that resolves to a public IP during validation and subsequently resolves to a private IP during execution, an attacker can access sensitive local services and potentially exfiltrate data. This issue has been patched in version 0.3.0.

Affected: Go: github.com/Tencent/WeKnora

### Summary

A DNS rebinding vulnerability in the `web_fetch` tool allows an unauthenticated attacker to bypass URL validation and access internal resources on the server, including private IP addresses (e.g., 127.0.0.1, 192.168.x.x). By crafting a malicious domain that resolves to a public IP during validation and subsequently resolves to a private IP during execution, an attacker can access sensitive local services and potentially exfiltrate data.

### Details

The vulnerability exists because the `web_fetch` tool lacks complete DNS pinning. The application performs URL validation only once via `validateParams()`, but the URL is then passed unchanged to the `fetchHTMLContent()` function, which eventually reaches `fetchWithChromedp()`. The headless browser (Chromedp) resolves the hostname independently without DNS pinning, allowing a time-of-check-time-of-use (TOCTOU) attack.

**Validation phase (first DNS resolution):** ```go if err := t.validateParams(p); err != nil { // Returns error for private IPs results[index] = &webFetchItemResult{ err: err, // ... } return } ```

**Execution phase (second DNS resolution):** The original URL (not the resolved IP) is passed through the execution chain: ```go output, data, err := t.executeFetch(ctx, p) // Calls fetchHTMLContent(ctx, targetURL) where targetURL is the original hostname ```

**Chromedp execution (vulnerable DNS resolution):** ```go func (t *WebFetchTool) fetchWithChromedp(ctx context.Conte…