validate_url() resolves DNS to check IPs but discards the result; the
HTTP client resolves again independently. Between those two lookups an
attacker can swap the DNS record from a public IP to an internal one
(DNS rebinding).
Push the IP-is-global check into the actual connection layer so the
validated resolution is the one used for the TCP connect:
- aiohttp (_fetch): _SSRFSafeResolver wraps DefaultResolver and rejects
non-global IPs at resolve time (zero TOCTOU window).
- requests (_scrape): _SSRFSafeAdapter mounts custom urllib3 connection
classes whose _new_conn resolves, validates, and connects to the
validated IP in one shot (zero TOCTOU window).
Both paths respect ENABLE_RAG_LOCAL_WEB_FETCH (skip validation when on).
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
