CVE-2026-55245

Bifrost: SSRF deny-list incomplete: isPublicIP permits CGNAT, IPv6 6to4/NAT64, and site-local in FetchAndEncodeURL

Published: Aug 28, 2026Updated: Sep 9, 2026 Sources: CVE List NVDCWE-918

N/ACVSS

NVD MITRE

Description

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.

No summary for this CVE yet.

Weaknesses

CWE-918

Affected Products

maximhq

bifrost

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

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References

https://github.com/maximhq/bifrost/security/advisories/GHSA-w98g-5w9p-p3rc

github.com

https://github.com/maximhq/bifrost/pull/4092

github.com

https://github.com/maximhq/bifrost/commit/54ec431fc5255ff42c36420d88549477e0b33d89

github.com

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News mentions

Critical Bifrost AI Gateway Flaw Lets Attackers Run Commands Without Credentials
en·The Hacker News·Sep 22, 2026 PoC Bifrost AI Gateway ai-ml

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