CVE-2026-110240
Description
A flaw was found in Lancet. This vulnerability can lead to unauthorized access and information disclosure through a Server-Side Request Forgery (SSRF) protection bypass. The internal address validation logic incorrectly classifies private and transition IPv6 (Internet Protocol version 6) addresses as external. A remote attacker can exploit this issue by supplying hostnames that resolve to these address forms, enabling requests to reach restricted internal services and cloud metadata endpoints.
Statement
This vulnerability is rated as having Moderate severity because successful exploitation requires an application to rely on Lancet's IP validation logic for security boundaries, limiting the blast radius to SSRF boundary bypass rather than remote code execution. Standard Red Hat platforms do not include or depend on this Go utility library by default, which restricts overall exposure across typical environments. Where applications integrate this library to sanitize network destinations, an external caller could circumvent address filtering if internal network services or metadata interfaces are reachable via transition protocols.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Access Control
Technical Impact: Bypass Protection Mechanism
By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
