CVE-2026-73297 in UFO
Summary
by MITRE • 08/12/2026
Microsoft UFO open-source framework for intelligent automation across devices and platforms. Prior to 3.0.8, _is_blocked_ip in ufo/utils/url_security.py did not block NAT64 prefixes 64:ff9b::/96 and 64:ff9b:1::/48, the 6to4 prefix 2002::/16, or the Teredo prefix 2001::/32 and did not re-check embedded IPv4 destinations, allowing an unauthenticated remote attacker who can influence URLs processed by validate_url to bypass the SSRF guard and reach cloud metadata, internal services, or localhost. This issue is fixed in version 3.0.8.
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Analysis
by VulDB Data Team • 08/12/2026
The Microsoft UFO framework represents a sophisticated intelligent automation solution designed to operate across diverse computing environments and platforms. This open-source project facilitates automated workflows and device management capabilities that span multiple network domains. The security vulnerability under examination resides within the URL validation mechanisms of the framework's utility modules, specifically in the ufo/utils/url_security.py file. Prior to version 3.0.8, the framework contained a critical flaw in its server-side request forgery (SSRF) protection system that fundamentally compromised its security posture.
The technical implementation flaw manifests in the _is_blocked_ip function which fails to properly identify and block specific IPv6 address prefixes that are commonly used for network address translation and tunneling purposes. The function specifically omits blocking NAT64 prefixes including 64:ff9b::/96 and 64:ff9b:1::/48, the 6to4 prefix 2002::/16, and the Teredo prefix 2001::/32. These prefixes are standardized mechanisms for translating between IPv4 and IPv6 addressing schemes that allow IPv4 traffic to traverse IPv6 networks. The vulnerability stems from the function's inability to re-check embedded IPv4 destinations that may be hidden within these IPv6 addresses, creating a pathway for attackers to bypass security controls.
This flaw creates a significant operational impact by allowing unauthenticated remote attackers to exploit the framework's URL processing capabilities. When an attacker can influence URLs that are processed through the validate_url function, they can construct malicious requests that leverage these bypassed prefixes to reach internal cloud metadata services, localhost endpoints, or other internal network resources that should normally be protected from external access. The vulnerability operates at the intersection of network protocol translation and security boundary enforcement, where legitimate IPv6 address translation mechanisms become attack vectors.
The security implications extend beyond simple access bypass as this vulnerability enables attackers to potentially gather sensitive information from cloud metadata services such as AWS EC2 metadata endpoints or Azure instance metadata services. These services often contain credentials, instance identifiers, and other sensitive configuration data that could be exploited for further compromise of the affected systems. The attack vector represents a classic server-side request forgery scenario where network protocol translation mechanisms are misused to circumvent security controls.
This vulnerability aligns with CWE-918 Server-Side Request Forgery (SSRF) which specifically addresses flaws enabling attackers to manipulate server-side requests to access internal resources. From an ATT&CK framework perspective, this maps to T1071.004 Application Layer Protocol: DNS and potentially T1566 Credential Access through metadata service exploitation. The fix implemented in version 3.0.8 addresses the core issue by ensuring proper blocking of these specific IPv6 prefixes and implementing comprehensive re-checking of embedded IPv4 destinations within translated addresses.
Organizations utilizing the UFO framework should prioritize immediate patching to version 3.0.8 or later to mitigate this vulnerability. System administrators should also implement network-level monitoring for unusual traffic patterns involving these specific IPv6 prefixes, as well as conduct security reviews of URL processing components throughout their infrastructure. The vulnerability demonstrates the importance of comprehensive protocol handling in security controls and highlights how standard translation mechanisms can be exploited when not properly accounted for in security validation logic.