CVE-2021-43717: Epson iProjection Auth Bypass Flaw

CVE-2021-43717 Overview

CVE-2021-43717 affects the Epson iProjection Android application (Epson iProjection.apk v3.2.6) used with the Epson EH-TW5350 projector. The application contains hardcoded authentication information that allows an attacker to access and control any projector equipped with the iProjection function. An attacker who identifies a reachable iProjection-enabled projector can use these embedded credentials to take control of the device and issue malicious commands.

Critical Impact
Attackers with network access to an iProjection-capable Epson projector can authenticate using hardcoded credentials and manipulate projector functionality without user consent.

Affected Products

Epson iProjection Android application (Epson iProjection.apk) version 3.2.6
Epson EH-TW5350 projector paired with the iProjection function
Additional Epson projector models supporting the iProjection feature may be affected

Discovery Timeline

2026-08-18 - CVE-2021-43717 published to NVD
2026-08-18 - Last updated in NVD database

Technical Details for CVE-2021-43717

Vulnerability Analysis

The vulnerability is a Hardcoded Credentials weakness in the mobile client used to control Epson projectors. The Epson iProjection.apk package ships with static authentication material that the client uses to negotiate access to the projector's iProjection service. Because the credential is baked into the distributed application binary, every deployed projector accepts the same secret.

Any party that extracts the credentials from the APK can reuse them against any reachable projector on a local network or across any network path exposing the iProjection service. The projector performs no additional verification tied to the specific user or client instance.

Root Cause

The root cause is the use of hardcoded authentication information in the shipped Android client. Static secrets embedded in mobile applications are trivially recoverable through reverse engineering of the APK. See the GitHub Advisory for CVE-2021-43717 for the technical details published by the reporter.

Attack Vector

An attacker on the same network as a target projector locates the device by scanning for the iProjection service. The attacker then authenticates using the credentials recovered from the mobile application and issues control commands. No user interaction on the projector or the legitimate mobile client is required.

No verified public exploit code is available. The vulnerability mechanism is documented in the referenced GitHub advisory without a released proof-of-concept.

Detection Methods for CVE-2021-43717

Indicators of Compromise

Unexpected projector state changes such as input source switches, power cycles, or displayed content changes originating from unknown clients
iProjection service authentication events from IP addresses outside the expected user population
Presence of the vulnerable Epson iProjection.apk v3.2.6 on enrolled mobile devices

Detection Strategies

Enumerate networks for Epson projectors exposing the iProjection service and correlate observed connections against an approved client inventory
Inspect wireless and wired network segments hosting AV equipment for unauthorized clients connecting to projector management ports
Alert on repeated authentication activity to projector services from devices not enrolled in mobile device management

Monitoring Recommendations

Log and review all network traffic between mobile devices and projectors, including source device identity
Monitor mobile device management inventories for installations of Epson iProjection.apk and enforce version control
Track physical projector behavior via facility telemetry and reconcile against scheduled use

How to Mitigate CVE-2021-43717

Immediate Actions Required

Isolate iProjection-capable projectors on a dedicated VLAN with access limited to authorized presenter devices
Disable the iProjection network feature on affected projectors when it is not actively required
Remove or restrict the vulnerable Epson iProjection.apk v3.2.6 from managed mobile devices until a vendor fix is confirmed

Patch Information

No vendor patch is referenced in the available advisory data. Consult Epson support channels for the latest firmware and application updates addressing hardcoded credential exposure. The published reference is the GitHub Advisory for CVE-2021-43717.

Workarounds

Physically disconnect projectors from networks when iProjection functionality is not in use
Enforce network-layer access control lists that only permit projector connections from a known set of presenter devices
Require a separate authenticated Wi-Fi network for AV equipment, segmented from corporate and guest networks

bash

# Example: restrict projector VLAN access via ACL (Cisco IOS syntax)
access-list 150 permit ip host 10.20.30.10 host 10.99.0.5
access-list 150 permit ip host 10.20.30.11 host 10.99.0.5
access-list 150 deny   ip any host 10.99.0.5 log
access-list 150 permit ip any any
interface Vlan99
 description AV-Projectors
 ip access-group 150 in