CVE-2019-9901: Envoyproxy Envoy

Critical severity, CVSS 10.0. EPSS: 5% chance of exploitation in the next 30 days.

Envoy 1.9.0 and before does not normalize HTTP URL paths. A remote attacker may craft a relative path, e.g., something/../admin, to bypass access control, e.g., a block on /admin. A backend server could then interpret the non-normalized path and provide an attacker access beyond the scope provided for by the access control policy.

Affected products

• Envoyproxy Envoy: up to and including 1.9.0

Published 2019-04-25. Last modified 2026-06-17.