is_string_allowed does endswith() matching and was called with the full URL
(retrieval/web/utils.py) against WEB_FETCH_FILTER_LIST, so a blocklisted host with any
path (https://blocked.example/x) ended with /x, not the host, and slipped through; the
allowlist direction false-rejected legitimate URLs and admitted attacker URLs ending in
an allowed string. The same endswith caused label confusion at the hostname call site
(retrieval/web/main.py): corp.com matched evilcorp.com, 10.0.0.1 matched 110.0.0.1.
Add is_host_allowed(host, ...) matching on DNS label boundaries (host == pattern or
host.endswith('.' + pattern)), called with the parsed hostname at both web-fetch call
sites. is_string_allowed is left unchanged for the unrelated function-name filters
(utils/middleware.py, utils/tools.py).
The separate is_global guard (validate_url / _ssrf_safe_new_conn, active when
ENABLE_RAG_LOCAL_WEB_FETCH is off) already blocks RFC1918/loopback/link-local, so this
restores the admin's intended blocking of specific public hosts.
Co-authored-by: addcontent <59762500+addcontent@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Timothy Jaeryang Baek