The UFO framework failed to block several IPv6 transition address prefixes—64:ff9b::/96, 64:ff9b:1::/48, 2002::/16 and 2001::/32—and did not re‑check embedded IPv4 destinations, allowing an unauthenticated attacker to supply a crafted URL to the validate_url routine. Because of this oversight the SSRF guard can be bypassed, permitting the attacker to reach cloud‑metadata services, internal network resources or localhost addresses. This flaw is an instance of CWE‑918, a server‑side request forgery vulnerability, and the primary impact is access to sensitive internal data or services that can be leveraged for further exploitation.

Microsoft's UFO open‑source automation framework is affected. Any installation using versions earlier than 3.0.8 runs the defective _is_blocked_ip helper in ufo/utils/url_security.py, which fails to filter the IPv6 transition prefixes 64:ff9b::/96, 64:ff9b:1::/48, the 6to4 prefix 2002::/16 and the Teredo prefix 2001::/32, and does not re‑evaluate embedded IPv4 addresses. The flaw applies to all deployments that pass external URL data to the validate_url function without additional safeguards.

The CVSS score for this issue is 6.9, indicating medium severity. The EPSS score of 2% suggests a low, but nonzero, likelihood of exploitation, and the vulnerability is not listed in the CISA KEV catalog. Attackers can exploit it by supplying a malicious URL to an unauthenticated user‑facing endpoint that calls validate_url, thereby bypassing the SSRF guard and communicating with internal services. The fix is available in UFO 3.0.8, so upgrading removes the risk. Until upgrading, the exposure remains until mechanisms are added to block the affected prefixes or otherwise validate URLs.