SSRF via unblocked IPv6 transition addresses
Published Aug 12, 2026 · Updated Aug 12, 2026
SSRF in Microsoft UFO before 3.0.8 allows remote attackers to reach internal services through IPv6 transition addresses. The _is_blocked_ip function in ufo/utils/url_security.py omits NAT64, 6to4, and Teredo prefixes from its blocked networks and fails to re-check their embedded IPv4 destinations. Reachability requires influence over a URL processed by validate_url; successful bypasses can access cloud metadata, private-network services, or localhost.
Summary
What happened
SSRF in Microsoft UFO before 3.0.8 allows remote attackers to reach internal services through IPv6 transition addresses. The _is_blocked_ip function in ufo/utils/url_security.py omits NAT64, 6to4, and Teredo prefixes from its blocked networks and fails to re-check their embedded IPv4 destinations. Reachability requires influence over a URL processed by validate_url; successful bypasses can access cloud metadata, private-network services, or localhost.
The record
- CVE
- CVE-2026-73297
- Published
- Aug 12, 2026
- Updated
- Aug 12, 2026
- Vendor
- Microsoft
- Product
- UFO
- Classifications
- CWE-918
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 12, 2026CVE publishedPublication date reported by the CVE source.
- Aug 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.0.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- IPv6 transition-address SSRF bypass examplesproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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