GHSA-28f5-38xr-jh2w java-client Allows Network Pivot via Unvalidated directConnect Redirect in AppiumCommandExecutor

• Maven io.appium:java-client: >= 8.2.1, < 10.1.1 → fixed in 10.1.1

Summary When `directConnect(true)` is enabled, appium/java-client unconditionally accepts `directConnectHost`, `directConnectPort`, and `directConnectPath` from the server's NEW_SESSION response and silently redirects all subsequent session traffic to the attacker-specified endpoint — with no allowlist, no host validation, and no user notification. Affected Code • `AppiumCommandExecutor.java` (line 196–219): `setDirectConnect()` builds a new URL from server-supplied fields and calls `overrideServerUrl(newUrl)` without validating host/IP. • `DirectConnect.java`: `getUrl()` constructs `protocol://host:port/path` with no allowlist. Root Cause Only the protocol is validated (must equal "https"). The destination host and port are never checked against any allowlist or denylist. PoC (confirmed) A rogue server injecting `directConnectHost=127.0.0.1:4443` causes the client to silently redirect all post-session commands: [bootstrap] POST /wd/hub/session [bootstrap] Injecting directConnect -> https://127.0.0.1:4443/wd/hub [redirect-target] HIT #1: GET /wd/hub/session/poc-session-001/source [redirect-target] HIT #2: DELETE /wd/hub/session/poc-session-001 Original source code unmodified — confirmed via `git diff HEAD` (empty). Evidence Screenshots Screenshot 1 — Rogue server capturing redirected traffic: Screenshot 2 — Java client processing response from attacker host: Impact • Full interception of session traffic • Network pivot to internal hosts (RFC-1918, 169.254.169.254) • Cloud credential theft via IMDS endpoint • Escalates to ~8.1 High in CI/CD environments where directConnect(true) is set in shared base configuration Suggested Fix Add allowlist validation before `overrideServerUrl()` is called, and/or block RFC-1918/loopback/link-local destinations by default. poc_appium_directconnect.zip