{"id":"CVE-2026-55096","published":"2026-09-28T17:17:50.007","lastModified":"2026-09-28T17:17:50.007","description":"fast-mcp-telegram is a Telegram MCP Server. Prior to version 30.1, the send_message/send_message_to_phone MCP tools accept files as a list of http(s) URLs, which the server downloads and attaches to the outgoing Telegram message. Downloads are guarded by _validate_url_security, an SSRF denylist that checks the URL's literal hostname string but never resolves DNS. The fetch (httpx.AsyncClient.get) does its own resolution at request time. Consequently a hostname that resolves to a loopback / private / link-local address passes the guard and is fetched — even with the secure defaults block_private_ips=True and allow_http_urls=False. Because the fetched body is returned to the attacker as a Telegram file attachment, this is a full-read, exfiltrating SSRF, not blind. This issue has been patched in version 30.1.","cvssScore":7.1,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","cwes":["CWE-184","CWE-918"],"vendors":[],"products":[],"references":[{"url":"https://github.com/leshchenko1979/fast-mcp-telegram/commit/e6b3032cfc906e14f5b84f2c2b8ec378eb457e57","tags":[]},{"url":"https://github.com/leshchenko1979/fast-mcp-telegram/releases/tag/0.30.1","tags":[]},{"url":"https://github.com/leshchenko1979/fast-mcp-telegram/security/advisories/GHSA-xr72-j7vj-vp7g","tags":[]}],"exploitRefs":[{"url":"https://github.com/leshchenko1979/fast-mcp-telegram/commit/e6b3032cfc906e14f5b84f2c2b8ec378eb457e57","tags":[]},{"url":"https://github.com/leshchenko1979/fast-mcp-telegram/releases/tag/0.30.1","tags":[]},{"url":"https://github.com/leshchenko1979/fast-mcp-telegram/security/advisories/GHSA-xr72-j7vj-vp7g","tags":[]}],"hasPoc":true,"ai":null}