CVE-2021-29492
Fixed in a distro release EPSS 63%CVSS 8.1
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.
Products: envoyproxy envoy
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Arch Linux | istio | 1.10.0-1 |
| Red Hat service mesh 1.1 | servicemesh | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-citadel | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-galley | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-istioctl | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-mixc | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-mixs | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-pilot-agent | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-pilot-discovery | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-proxy | 0:1.1.14-1.el8 |
| Red Hat service mesh 1.1 | servicemesh-sidecar-injector | 0:1.1.14-1.el8 |
| Red Hat service mesh 2.0 | servicemesh | 0:2.0.4-1.el8 |
| Red Hat service mesh 2.0 | servicemesh-istioctl | 0:2.0.4-1.el8 |
| Red Hat service mesh 2.0 | servicemesh-mixc | 0:2.0.4-1.el8 |
| Red Hat service mesh 2.0 | servicemesh-mixs | 0:2.0.4-1.el8 |
| Red Hat service mesh 2.0 | servicemesh-operator | 0:2.0.4-3.el8 |
| Red Hat service mesh 2.0 | servicemesh-pilot-agent | 0:2.0.4-1.el8 |
| Red Hat service mesh 2.0 | servicemesh-pilot-discovery | 0:2.0.4-1.el8 |
| Red Hat service mesh 2.0 | servicemesh-proxy | 0:2.0.4-1.el8 |