CVE-2025-21020
📋 TL;DR
This vulnerability allows local privileged attackers to write out-of-bounds memory when creating bitmap images in Blockchain Keystore. It affects systems running Blockchain Keystore versions prior to 1.3.17.2. Attackers need local access with elevated privileges to exploit this flaw.
💻 Affected Systems
- Blockchain Keystore
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Privilege escalation leading to full system compromise, arbitrary code execution, or denial of service through memory corruption.
Likely Case
Local privilege escalation allowing attackers to gain higher privileges on the affected system.
If Mitigated
Limited impact due to proper access controls and privilege separation preventing local attackers from reaching vulnerable components.
🎯 Exploit Status
Exploitation requires local privileged access and knowledge of memory layout. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.3.17.2
Vendor Advisory: https://security.samsungmobile.com/serviceWeb.smsb?year=2025&month=08
Restart Required: No
Instructions:
1. Update Blockchain Keystore to version 1.3.17.2 or later via Samsung device updates. 2. Apply the August 2025 Samsung security update to affected devices. 3. Verify the update was successful by checking the version.
🔧 Temporary Workarounds
Restrict local privileged access
allLimit local administrative access to prevent potential attackers from reaching the required privilege level.
🧯 If You Can't Patch
- Implement strict access controls to limit local privileged user accounts
- Monitor for suspicious local privilege escalation attempts and memory corruption events
🔍 How to Verify
Check if Vulnerable:
Check Blockchain Keystore version on Samsung device: Settings > Apps > Blockchain Keystore > App infoCheck Version:
adb shell dumpsys package com.samsung.android.blockchain | grep versionNameVerify Fix Applied:
Verify Blockchain Keystore version is 1.3.17.2 or later after applying Samsung security updates📡 Detection & Monitoring
Log Indicators:
- Memory corruption events in system logs
- Unexpected privilege escalation attempts
- Crash reports from Blockchain Keystore process
Network Indicators:
- None - local exploitation only
SIEM Query:
source="android_system" AND (event="memory_corruption" OR process="Blockchain Keystore" AND event="crash")