CVE-2026-110719 in gateway
Summary
by MITRE • 10/15/2026
Portkey AI Gateway 1.14.0 through 1.15.2 contains a server-side request forgery vulnerability that allows unauthenticated attackers to reach loopback and Docker host services because isValidCustomHost trusts localhost-style hosts when TRUSTED_CUSTOM_HOSTS is unset. Attackers can send /v1 requests with a crafted x-portkey-custom-host header, such as via the ollama provider, to make the gateway call internal services and return their responses.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified in Portkey AI Gateway versions 1.14.0 through 1.15.2 represents a critical server-side request forgery flaw rooted in improper validation of custom host headers. This security defect allows unauthenticated attackers to bypass intended network boundaries and interact with internal services, specifically targeting loopback addresses and Docker host environments. The core technical issue lies within the isValidCustomHost function, which is responsible for validating the destination hosts specified by clients. When the TRUSTED_CUSTOM_HOSTS environment variable is not configured or remains unset, the validation logic fails to adequately restrict requests directed at localhost-style addresses. This oversight effectively creates an open proxy scenario where the gateway acts as a conduit for malicious traffic destined for internal infrastructure that should remain inaccessible from external networks.
From a technical perspective, the exploitation mechanism relies on the manipulation of HTTP headers during API interactions with the AI Gateway. Attackers can target endpoints such as /v1 by injecting crafted values into the x-portkey-custom-host header. This technique is particularly effective when interacting with providers like Ollama, which may route requests based on these custom host directives. By specifying internal IP addresses or localhost identifiers within this header, an attacker forces the gateway to initiate connections toward services running on the same network segment or container environment as the gateway itself. The gateway then retrieves responses from these internal services and relays them back to the unauthenticated client, effectively exposing sensitive data or administrative interfaces that are not meant for public access.
The operational impact of this vulnerability is severe due to its potential to facilitate lateral movement within a compromised network environment. By leveraging this server-side request forgery capability, an attacker can probe internal services such as databases, management consoles, or other microservices running on the Docker host or local machine. This exposure can lead to unauthorized data access, configuration manipulation, or further exploitation of vulnerabilities present in those internal services. Since the attack requires no authentication, it significantly lowers the barrier for entry, allowing any internet-facing instance of the vulnerable gateway version to be exploited remotely without prior credentials.
This vulnerability aligns with CWE-918, which describes Server-Side Request Forgery (SSRF), specifically involving the lack of restrictions on internal network access. In terms of offensive security frameworks, this behavior corresponds to ATT&CK technique T1572, Protocol Tunneling, where an attacker uses a legitimate protocol or service to establish communication with internal resources. The failure to validate and sanitize custom host inputs against a whitelist when no trusted hosts are explicitly defined constitutes a fundamental design flaw in the access control logic of the application.
To mitigate this risk, organizations running Portkey AI Gateway versions 1.14.0 through 1.15.2 should immediately upgrade to a patched version where the isValidCustomHost function has been hardened to reject localhost-style addresses regardless of configuration states. In environments where upgrading is not immediately feasible, administrators can implement a workaround by explicitly setting the TRUSTED_CUSTOM_HOSTS environment variable with a strict whitelist of allowed external domains. This ensures that even if custom host headers are provided, only pre-approved destinations will be permitted for request forwarding. Additionally, deploying network-level controls such as firewall rules to restrict outbound connections from the gateway container or server can provide an additional layer of defense against SSRF exploitation attempts targeting internal services.