CVE-2026-85692

MEDIUM 6.5

Nightingale 9.1.1 SSRF Guard Bypass via IPv6 Encoding

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

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 http_fetch 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 http_fetch 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.

CWE	CWE-918
Vendor	ccfos
Product	nightingale
Published	Sep 4, 2026
Last Updated	Sep 4, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

ccfos / nightingale

0 ≤ 9.1.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/ccfos/nightingale/issues/3363 github.com: https://github.com/ccfos/nightingale github.com: https://github.com/ccfos/nightingale/blob/v9.1.1/aiagent/tools/http.go vulncheck.com: https://www.vulncheck.com/advisories/nightingale-9.1.1-ssrf-guard-bypass-via-ipv6-encoding

Credits

George Chen