GHSA-28f5-38xr-jh2w
java-client Allows Network Pivot via Unvalidated directConnect Redirect in AppiumCommandExecutor
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Maven | io.appium:java-client | >= 8.2.1, < 10.1.1 | 10.1.1 |
Details
As written in the advisory (Markdown source, shown as plain text).
## 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:**
<img width="887" height="146" alt="1" src="https://github.com/user-attachments/assets/cc28002c-ea20-4ac8-8336-cec632e3c842" />
**Screenshot 2 — Java client processing response from attacker host:**
<img width="788" height="130" alt="2" src="https://github.com/user-attachments/assets/222cbab0-0d53-45b2-847d-6aa4e3b79370" />
## 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](https://github.com/user-attachments/files/26472525/poc_appium_directconnect.zip)
References
External links from the advisory. They lead to third-party sites.
- https://github.com/appium/java-client/security/advisories/GHSA-28f5-38xr-jh2w
- https://github.com/appium/java-client/pull/2408
- https://github.com/appium/java-client/commit/2b9cd442b9dbf56ccc6f1e83aeeb411c0ec230c9
- https://github.com/appium/java-client
- https://github.com/appium/java-client/releases/tag/v10.1.1