CVE-2021-29492

Envoy is a cloud-native edge/middle/service proxy. Envoy does not decode escaped slash sequences `%2F` and `%5C` in HTTP URL paths in versions 1.18.2 and before. A remote attacker may craft a path with escaped slashes, e.g. `/something%2F..%2Fadmin`, to bypass access control, e.g. a block on `/admin`. A backend server could then decode slash sequences and normalize path and provide an attacker access beyond the scope provided for by the access control policy. ### Impact Escalation of Privileges when using RBAC or JWT filters with enforcement based on URL path. Users with back end servers that interpret `%2F` and `/` and `%5C` and `` interchangeably are impacted. ### Attack Vector URL paths containing escaped slash characters delivered by untrusted client. Patches in versions 1.18.3, 1.17.3, 1.16.4, 1.15.5 contain new path normalization option to decode escaped slash characters. As a workaround, if back end servers treat `%2F` and `/` and `%5C` and `` interchangeably and a URL path based access control is configured, one may reconfigure the back end server to not treat `%2F` and `/` and `%5C` and `` interchangeably.

Link	Resource
https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf	Mitigation Third Party Advisory

Configuration 1

cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*

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Published : 2021-05-28 09:15

Updated : 2021-12-10 06:10

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NVD link : CVE-2021-29492

Mitre link : CVE-2021-29492

No products.

CWE-22