What is CVE-2025-66405?

CVE-2025-66405 is a critical-severity vulnerability in Portkey Gateway, classified under Server-Side Request Forgery (SSRF). CVSS score: 9.8/10. Published 2025-12-01.

How severe is CVE-2025-66405?

Critical severity. CVSS v3 base score is 9.8 out of 10.

SSRF in Portkey Gateway

CVE-2025-66405

Portkey.ai Gateway is a blazing fast AI Gateway with integrated guardrails. Prior to 1.14.0, the gateway determined the destination baseURL by prioritizing the value in the x-portkey-custom-host request header. The proxy route then appends the client-specified path to perform an external fetch. This can be maliciously used by users for SSRF attacks. This vulnerability is fixed in 1.14.0.

Vulnerability class: SSRF (Server-Side Request Forgery)

Published 2025-12-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (28.6th percentile), scored 2026-10-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Portkey Gateway
Portkey-Ai Gateway — versions < 1.14.0

Weakness classification (CWE)

CWE-918 — Server-Side Request Forgery (SSRF)

References

github.com/Portkey-AI/gateway/security/advisories/GHSA-hhh5-2cvx-vmfp (Vendor Advisory)
github.com/Portkey-AI/gateway/pull/1372 (Issue Tracking)
github.com/Portkey-AI/gateway/commit/b5a7825ba5f4e6918deb32d9969899ce2229a885 (Patch)

Frequently asked questions

What is CVE-2025-66405?: CVE-2025-66405 is a critical-severity vulnerability in Portkey Gateway, classified under Server-Side Request Forgery (SSRF). CVSS score: 9.8/10. Published 2025-12-01.
How severe is CVE-2025-66405?: Critical severity. CVSS v3 base score is 9.8 out of 10.