CVE-2026-55245: Maximhq Bifrost

High severity, CVSS 8.7. EPSS: 0.6% chance of exploitation in the next 30 days.

Bifrost is an enterprise AI gateway for routing requests to model providers. Prior to 1.5.17, the isPublicIP function in core/providers/utils/fetch.go, reached through FetchAndEncodeURL for Bedrock and Vertex image or document URLs, classifies Carrier-Grade NAT 100.64.0.0/10, IPv6 6to4 2002::/16, NAT64 64:ff9b::/96 and 64:ff9b:1::/48, and deprecated IPv6 site-local fec0::/10 addresses as public. A remote attacker who controls a multimodal request URL can make the gateway fetch internal services, including a cloud instance metadata endpoint encoded through 6to4 or NAT64. This issue is fixed in version 1.5.17.

Affected products

• Maximhq Bifrost: before 1.5.17 (fixed in 1.5.17)

Published 2026-08-28. Last modified 2026-09-09.