CVE-2025-26781
📋 TL;DR
A vulnerability in Samsung Exynos processors' L2 layer incorrectly handles RLC AM PDUs, allowing attackers to cause denial of service. This affects Samsung mobile devices, wearables, and modems using the listed Exynos chips. The vulnerability impacts device availability and requires physical or network proximity.
💻 Affected Systems
- Samsung Mobile Processor Exynos 980, 990, 850, 1080, 2100, 1280, 2200, 1330, 1380, 1480
- Samsung Wearable Processor Exynos 9110, W920, W930
- Samsung Modem Exynos 5123, 5300
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device/service unavailability requiring hardware reset or service intervention, potentially affecting critical communication functions in mobile networks.
Likely Case
Temporary service disruption affecting device connectivity, call drops, or data transmission failures until system recovers or reboots.
If Mitigated
Limited impact with proper network segmentation and monitoring, though devices remain vulnerable to targeted attacks.
🎯 Exploit Status
Exploitation requires sending specially crafted RLC AM PDUs to the affected device, which could be achieved via malicious base station or network man-in-the-middle position.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Vendor-specific firmware updates
Vendor Advisory: https://semiconductor.samsung.com/support/quality-support/product-security-updates/cve-2025-26781/
Restart Required: Yes
Instructions:
1. Check Samsung security advisory for device-specific updates. 2. Apply firmware updates through device settings or Samsung Smart Switch. 3. For carrier-locked devices, wait for carrier-approved updates. 4. Reboot device after update installation.
🔧 Temporary Workarounds
Network segmentation
allIsolate affected devices from untrusted networks to reduce attack surface
Disable unnecessary wireless interfaces
allTurn off Wi-Fi, Bluetooth, and mobile data when not needed to limit exposure
🧯 If You Can't Patch
- Monitor device behavior for unexpected disconnections or service disruptions
- Implement network monitoring for unusual RLC protocol patterns
🔍 How to Verify
Check if Vulnerable:
Check device model and chipset information in Settings > About phone > Hardware infoCheck Version:
Settings > About phone > Software information > Build number/Baseband versionVerify Fix Applied:
Verify firmware version matches patched version in Samsung security advisory and check for security patch level📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots
- Radio interface failures
- Modem crash logs
Network Indicators:
- Abnormal RLC protocol patterns
- Unexpected radio resource control messages
SIEM Query:
Device logs showing 'modem crash', 'radio failure', or 'unexpected reset' events on Samsung Exynos devices