CVE-2026-9221: Setracker2 MD5 Authentication Bypass – Session Hijacking Risk

Technical summary

CVE-2026-9221 affects Setracker2 (package com.tgelec.setracker) version 3.1.5 and earlier. The vulnerability stems from reliance on MD5, a cryptographic hash function that is collision-prone and unsuitable for authentication. The app uses MD5 to generate request signatures for REST API authentication between client and backend. An attacker with network visibility can observe signed requests, reverse-engineer the MD5 signature to extract the underlying session ID, and subsequently forge authenticated API calls impersonating the legitimate user. The attack requires no user interaction and can be executed over the network.

Business impact

Users of Setracker2 face unauthorized account access risk. Attackers gaining a valid session ID could modify personal data, change device settings, access location history if tracked, or perform actions tied to the user's account. For organizations deploying Setracker2 or similar wearable companion apps as part of employee wellness or safety programs, this exposes both employee privacy and potential compliance violations if user data is exposed or altered. The reputational and legal consequences depend on the sensitivity of data stored in Setracker2 accounts.

Affected systems

Setracker2 Android app (com.tgelec.setracker) version 3.1.5 and all earlier versions are affected. The vulnerability impacts any device running these versions that communicates with Setracker2's backend services. iOS versions and newer Android releases (version 3.1.6 and later, once released) are expected to be unaffected, pending vendor confirmation of remediation details.

Exploitability

Exploitability is moderate-to-high. The attack vector is network-based with no authentication or user interaction required. However, the attacker must have network access to observe encrypted HTTPS traffic or be positioned to perform a man-in-the-middle attack to capture signed requests. In open Wi-Fi or compromised network environments, this becomes straightforward. The technical barrier to reversing MD5 and extracting a session ID is low for attackers with cryptographic knowledge, making this a practical threat for motivated adversaries.

Remediation

Users must upgrade to a patched version of Setracker2 once released by the vendor. The vendor should migrate from MD5-based signatures to HMAC-SHA-256 or stronger authenticated encryption (e.g., AES-GCM) for request signing. All existing sessions should be invalidated upon upgrade to prevent session reuse attacks. Organizations should verify patch availability and enforce app updates through Mobile Device Management (MDM) solutions where applicable.

Patch guidance

Monitor the official Setracker2 app store listing (Google Play Store) or vendor website for a security update addressing CVE-2026-9221. Patches are expected to replace MD5 signature generation with cryptographically secure alternatives. Update the app as soon as a version higher than 3.1.5 becomes available. If you manage Setracker2 deployment across a fleet of devices, use MDM tools to enforce automatic updates. Verify with the vendor that patched versions invalidate all pre-patch sessions to prevent session fixation.

Detection guidance

Monitor network logs for unusual API requests to Setracker2's backend with mismatched or repeated session identifiers. Inspect HTTP/HTTPS traffic for suspicious MD5 signatures being reused across different user accounts or timestamps. On affected devices, check installed app version via Settings > Apps > Setracker2; versions 3.1.5 and below require immediate updating. Security teams should flag any alerts indicating unauthorized Setracker2 API activity or account modifications from unexpected locations.

Why prioritize this

Despite a HIGH CVSS score of 7.5, this vulnerability prioritizes based on practical exploitability and business context. The network-based attack vector with no user interaction required, combined with the ease of cryptanalysis on MD5, makes this a credible threat. The impact is confidentiality-focused (session hijacking), not system-wide availability, which lowers urgency relative to RCE flaws. However, for organizations using Setracker2 as an employee wellness tool or for users storing sensitive location/health data, this merits urgent patching. Prioritize according to the sensitivity of data stored in Setracker2 accounts within your environment.

Risk score, explained

The CVSS 3.1 score of 7.5 (HIGH) reflects a network-accessible attack requiring no privileges or user interaction, resulting in high confidentiality impact (session hijacking). Integrity is marked as not affected because the CVE focuses on authentication bypass, not data tampering, though post-compromise an attacker could modify data. Availability is unaffected. The score appropriately reflects the ease of exploitation and the critical nature of session compromise, though real-world risk varies based on deployment context and data sensitivity.

Frequently asked questions