Affected: MervinPraison PraisonAI, MervinPraison praisonaiagents

PraisonAI is a multi-agent teams system. Prior to version 4.6.40 of PraisonAI, corresponding to version 1.6.40 of praisonaiagents, `spider_tools` URL validation can be bypassed using alternate loopback host encodings. The tool contains a URL validation function intended to block local or unsafe targets before fetching attacker-controlled URLs. However, the validation only blocks a small set of exact host strings such as `localhost` and `127.0.0.1`. It does not normalize hostnames, resolve DNS, parse numeric IPv4 variants, or validate the final resolved IP address before making the request. As a result, certain URLs may bypass the protection and still reach loopback services. After the weak validation passes, `scrape_page()` calls `requests.Session.get()` on the attacker-controlled URL. This allows an attacker who can influence URLs passed to `scrape_page`, `crawl`, or `extract_text` to induce SSRF requests against loopback-only services. This is a server-side request forgery protection bypass. PraisonAI version 4.6.40 and praisonaiagents version 1.6.40 contain a patch.