CVE-2026-69257: Flowise SSRF protection bypass via IPv4-mapped IPv6 addresses

Executive brief

Flowise, an open-source tool for building LLM applications, contains a security flaw in how it blocks access to restricted internal networks. An attacker can bypass these protections by using a specific type of network address (IPv4-mapped IPv6), allowing them to access sensitive internal services, cloud metadata, or the server's own local interface. This could lead to the theft of cloud credentials or unauthorized access to private databases and APIs.

Technical details

The vulnerability exists in the `isDeniedIP()` function within `httpSecurity.ts`. The implementation uses the `ipaddr.js` library to compare resolved IP addresses against a deny list but fails to normalize IPv4-mapped IPv6 addresses (e.g., `::ffff:127.0.0.1`) before performing a 'kind' check. Because the library identifies these as 'ipv6' while the deny list contains 'ipv4' CIDR ranges, the security check is bypassed. An attacker can exploit this by configuring a DNS AAAA record pointing to a mapped internal address, enabling SSRF against AWS/GCP/Azure metadata endpoints (169.254.169.254) or RFC1918 private networks. The issue is addressed in version 3.1.3.

Affected products

• FlowiseAI flowise <= 3.1.2

Timeline

• 2026-07-29: advisory: Original GitHub Advisory published
• 2026-08-04: patched: Advisory updated with patched version 3.1.3

References

• https://api.github.com/users/feiyang666
• https://github.com/feiyang666
• https://api.github.com/users/feiyang666/gists%7B/gist_id%7D
• https://api.github.com/users/feiyang666/repos
• https://avatars.githubusercontent.com/u/11484472?v=4
• https://api.github.com/users/feiyang666/events%7B/privacy%7D