CVE-2026-85692: Nightingale 9.1.1 SSRF Guard Bypass via IPv6 Encoding
Nightingale (n9e), as of commit 8362cbe (main branch, confirmed 2026-08-27), contains a server-side request forgery vulnerability in the isPublicIP function in aiagent/tools/http.go, the SSRF guard for the httpfetch AI-agent tool. The function only unwraps standard IPv4-mapped (::ffff:a.b.c.d) IPv6 addresses before checking them against the forbidden-range list, and does not classify 6to4 (2002::/16), NAT64 (64:ff9b::/96, 64:ff9b:1::/48), or deprecated site-local (fec0::/10) addresses. On a dual-stack or NAT64-enabled host, an attacker able to supply a URL to the httpfetch tool can bypass the guard by encoding a forbidden IPv4 address (such as the cloud instance-metadata endpoint 169.254.169.254) in one of these IPv6 forms to reach internal or metadata services.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to this bypass?
Deployments that expose the http_fetch AI-agent tool to an attacker-controlled URL are exposed when the host supports dual-stack networking or NAT64. The bypass can target internal services or cloud instance-metadata endpoints by representing a forbidden IPv4 destination in certain IPv6 forms.
What access does an attacker need?
An attacker needs low-privilege access sufficient to supply a URL to the http_fetch tool. No user interaction is required.
Which IPv6 address forms are not handled by the guard?
The guard does not classify 6to4 addresses in 2002::/16, NAT64 addresses in 64:ff9b::/96 or 64:ff9b:1::/48, or deprecated site-local addresses in fec0::/10. It only unwraps standard IPv4-mapped IPv6 addresses before applying its forbidden-range checks.