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.
{
"cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
"source": "CPE_RANGE",
"extracted_events": [
{
"introduced": "0"
},
{
"last_affected": "1.9.0"
}
]
}