Improper input validation in Samsung Members prior to version 5.5.01.3

CVE-2025-21079 is an improper input validation flaw in Samsung Members, the preloaded community, diagnostics, and support app on Galaxy smartphones. Versions prior to 5.5.01.3 allow a remote attacker to force the app to connect to an arbitrary URL and launch arbitrary Android activities using Samsung Members' own privilege context. Exploitation requires user interaction — the victim must click a malicious link. The vulnerability was demonstrated at Pwn2Own Ireland (October 2025) by Ken Gannon (Mobile Hacking Lab) and Dimitrios Valsamaras (Summoning Team / Microsoft), earning $50,000 as the first step of a four-CVE chain (CVE-2025-21079 → CVE-2025-58486 → CVE-2025-58487 → Bixby Capsule RCE) that achieved system-level code execution on a Galaxy S25. Affected devices include Galaxy S25, S24, and Flip 7. Samsung patched Members in the November 2025 service bulletin.

Samsung and NIST both rate this HIGH (Samsung 7.1, NIST 8.1), but that severity overstates the standalone risk for enterprise defenders. On its own, CVE-2025-21079 does not achieve code execution — it redirects Samsung Members to an attacker URL and can launch other app activities, which is a meaningful primitive only when chained with the Samsung Account XSS and Bixby Capsule bugs that were independently patched in December 2025. The affected component is a consumer support app with no privileged system role, no access to enterprise credentials, and no presence on servers or workstations. For a team managing 10,000 hosts, this touches only Samsung Galaxy phones in your mobile fleet — and even there, auto-updates through Galaxy Store will have silently patched most devices months ago.

Why this verdict

• No standalone code execution. CVE-2025-21079 alone achieves a URL redirect and activity launch — meaningful only as a chain primitive, not as an independent threat. The remaining three CVEs (CVE-2025-58486, CVE-2025-58487, Bixby Capsule) were independently patched in December 2025.
• User interaction required. The CVSS vector includes UI:R. The victim must tap a malicious link on their Samsung phone. Mobile phishing click-through rates are 3-5%, compounding downward.
• Role multiplier: Samsung Members occupies NO high-value enterprise role. It is a consumer support/diagnostics app. It is not an IdP, PAM, hypervisor, CI/CD, backup, database, kernel-mode agent, or network edge component. Its blast radius on successful exploitation is limited to a single mobile device with normal app sandbox permissions. No domain/fleet/supply-chain cascade is possible. The floor rule does not apply.
• Auto-update erosion. Samsung Members updates through Galaxy Store, which auto-updates by default. Nine months post-patch, the residual vulnerable population is a small tail of unmanaged or update-disabled devices.
• EPSS confirms low real-world risk. At 0.00406, this CVE sits well below the threshold where automated exploitation is expected.

Why not higher?

This is not HIGH because the vulnerability alone does not achieve code execution, the affected component has zero enterprise-infrastructure relevance, and the full chain requires three additional CVEs all independently patched months ago. There is no KEV listing, no in-the-wild exploitation, and no high-value-role deployment scenario for Samsung Members.

Why not lower?

This is not LOW because the vulnerability was demonstrated at Pwn2Own by credible researchers, it does provide a real exploitation primitive (arbitrary URL connection and activity launch under Members' privileges), and it affects a preloaded app on hundreds of millions of Samsung devices. The chain it enables — while requiring additional bugs — did achieve full system-level RCE on a flagship device, proving the primitive has real offensive value.

1. Verify Samsung Members version via MDM inventory — Query your MDM (Intune, Workspace ONE, SOTI, Knox Manage) for all Samsung devices running Members <5.5.01.3. Flag and force-update any stragglers. No mitigation SLA applies at MEDIUM — go straight to the 365-day remediation window per the noisgate remediation SLA.
2. Enforce Galaxy Store auto-updates — Use Knox or MDM policy to ensure Galaxy Store automatic updates are enabled. This is the primary patch delivery mechanism for Samsung preloaded apps and should have resolved this for most devices already.
3. Deploy Mobile Threat Defense — MTD solutions (Lookout, Zimperium, Microsoft Defender for Endpoint on Android) detect malicious URL opens and anomalous app behavior, breaking the chain at step 1.
4. Disable Bixby on managed devices if unused — If Bixby is not a business requirement, disabling it via Knox policy eliminates the final-stage RCE target in the demonstrated chain, even if Members remains unpatched.

Run this on your MDM server or auditor workstation where you can query device inventory. Requires adb access to a target Samsung device for direct checks, or adapt the logic into your MDM's compliance query. Example: adb shell dumpsys package com.samsung.android.voc | grep versionName

#!/bin/bash
# CVE-2025-21079 Samsung Members version check
# Run via ADB against a connected Samsung device
# Requires: adb access to target device (USB debugging enabled)
# Usage: ./check_cve_2025_21079.sh

PACKAGE="com.samsung.android.voc"
FIXED_VERSION="5.5.01.3"

if ! command -v adb &> /dev/null; then
  echo "UNKNOWN - adb not found in PATH"
  exit 2
fi

VERSION=$(adb shell dumpsys package "$PACKAGE" 2>/dev/null | grep versionName | head -1 | sed 's/.*versionName=//' | tr -d '[:space:]')

if [ -z "$VERSION" ]; then
  echo "UNKNOWN - Samsung Members ($PACKAGE) not found on device"
  exit 2
fi

# Compare versions using sort -V
LOWER=$(printf '%s\n%s' "$VERSION" "$FIXED_VERSION" | sort -V | head -1)

if [ "$VERSION" = "$FIXED_VERSION" ] || [ "$LOWER" = "$FIXED_VERSION" ]; then
  echo "PATCHED - Samsung Members version $VERSION >= $FIXED_VERSION"
  exit 0
else
  echo "VULNERABLE - Samsung Members version $VERSION < $FIXED_VERSION (CVE-2025-21079)"
  exit 1
fi

Sources

1. NVD - CVE-2025-21079
2. Samsung Mobile Security Bulletin (November 2025)
3. SecurityWeek - How a $50,000 Exploit Chain Turned Bixby Against Samsung Phones
4. HKCERT - Samsung Products Multiple Vulnerabilities
5. CVEMon - CVE-2025-21079 Overview
6. Samsung Security Update Portal
7. Sammy Fans - September 2025 Security Update Details