| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/envoyproxy/gateway | ≥ 1.8.0-rc.0, < 1.8.1< 1.7.4 | 1.8.11.7.4 |
The to_absolute_normalized_path function (security.lua:28-43) does not collapse redundant path separators (// → /). On Linux, //etc/passwd is equivalent to /etc/passwd (POSIX path semantics), but is_critical_path fails to match the double-slash variant because //etc/passwd does not start with /etc/.
This allows Lua code submitted as an EnvoyExtensionPolicy to read arbitrary files from the gateway controller pod's filesystem during Strict validation (the default), including:
/etc/passwd//var/run/secrets/kubernetes.io/serviceaccount/token//certs/...//proc/self/environThese credentials can be used to read sensitive information from the K8s API Server or from the Gateway XDS server.
This has been patched in versions >= v1.7.4 and v1.8.1
// to /) so double-slash variants like //etc/passwd and //var/run/secrets/... are matched by the critical-path check.. or .. segment in any position and across both separator styles (catches /etc/./passwd, ./etc/passwd, /etc/.).Please refer to the Warning section in Lua docs for measures to reduce risk.
Envoy Gateway thanks @dashingDragon and @Donjon-Cerberus for reporting this issue.
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