CVE-2025-43706 Overview
CVE-2025-43706 is a denial-of-service vulnerability affecting Samsung Mobile Processor, Wearable Processor, and standalone Modem product lines. The flaw resides in the Layer 2 (L2) handling of Radio Resource Control (RRC) packets within the baseband firmware. Attackers can send malformed RRC packets over the cellular network to trigger improper handling logic, causing the modem to enter an unrecoverable state. The issue is tracked under [CWE-400: Uncontrolled Resource Consumption]. The vulnerability impacts a broad range of Samsung silicon, including flagship Exynos application processors, Galaxy Watch wearable processors, and discrete 5G modems used in mobile devices.
Critical Impact
A remote, unauthenticated attacker within radio range or controlling a rogue base station can disrupt cellular connectivity on affected devices by transmitting crafted RRC packets.
Affected Products
- Samsung Exynos 980, 990, 850, 1080, 2400, 1580, 9110
- Samsung Exynos W920 and W930 Wearable Processors
- Samsung Modem 5123 and Modem 5400
Discovery Timeline
- 2026-01-05 - CVE-2025-43706 published to NVD
- 2026-01-09 - Last updated in NVD database
Technical Details for CVE-2025-43706
Vulnerability Analysis
The vulnerability stems from incorrect handling of Radio Resource Control (RRC) packets in the L2 layer of Samsung baseband firmware. RRC is the signaling protocol responsible for connection establishment, mobility, and configuration between user equipment and the cellular network. When the affected modem processes specially crafted RRC packets, the L2 implementation fails to validate or process them correctly, causing resource exhaustion or a fault condition that halts modem operation.
The issue is classified as [CWE-400: Uncontrolled Resource Consumption]. Successful exploitation results in loss of cellular service, which may persist until the device reboots or the modem stack is reinitialized. The vulnerability does not expose data confidentiality or integrity, but availability is fully compromised on the cellular interface.
Root Cause
The root cause is improper validation of RRC signaling messages within the L2 protocol stack. Samsung has not publicly disclosed the specific structure field or parsing routine at fault. The condition is reproducible without authentication because RRC messages are exchanged before any user-level authentication step in the cellular attach procedure.
Attack Vector
Attack delivery requires the adversary to transmit malicious RRC packets to a target device. This is typically achieved using a rogue or compromised base station, software-defined radio equipment such as srsRAN or OpenAirInterface, or a man-in-the-middle position on the radio access network. No user interaction or pairing is required.
No public proof-of-concept exploit code is available for CVE-2025-43706, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Technical details beyond Samsung's advisory have not been released.
Detection Methods for CVE-2025-43706
Indicators of Compromise
- Unexpected loss of cellular signal or modem reset events across multiple devices in the same physical area.
- Repeated baseband crash logs or modem subsystem restart entries in device diagnostic data.
- Presence of unauthorized cellular base stations or unusual radio frequency activity in the vicinity of affected devices.
Detection Strategies
- Monitor mobile device management (MDM) telemetry for elevated rates of cellular connectivity loss or modem firmware faults.
- Correlate device location data with reports of cell-site anomalies to identify potential rogue base station activity.
- Track firmware version inventories to identify devices running unpatched Exynos or Samsung Modem builds.
Monitoring Recommendations
- Enroll mobile fleets in MDM platforms that report baseband firmware versions and crash diagnostics.
- Use cellular threat intelligence feeds to identify rogue base station campaigns targeting enterprise users.
- Audit Samsung security bulletins regularly for updated patch information at the Samsung Product Security Updates portal.
How to Mitigate CVE-2025-43706
Immediate Actions Required
- Apply Samsung's firmware update for the affected Exynos chipset or Modem 5123/5400 as soon as it is distributed by the device OEM.
- Inventory all mobile devices, wearables, and IoT endpoints using affected Samsung silicon and prioritize patching.
- Advise high-risk users to avoid untrusted cellular networks and consider Wi-Fi-only operation in sensitive environments until patches are deployed.
Patch Information
Samsung has published advisory details for CVE-2025-43706 at the Samsung CVE-2025-43706 advisory page. Patches are delivered through device manufacturers as part of monthly Android security updates or wearable firmware releases. Verify the patch level reported by the device matches or exceeds the Samsung advisory baseline.
Workarounds
- Disable cellular radios on devices that do not require mobile connectivity, restricting them to Wi-Fi.
- Restrict device operation to known trusted carrier networks where feasible using carrier locking or network selection policies.
- Reboot devices to recover from denial-of-service conditions when modem subsystems become unresponsive.
# Configuration example: query Android baseband firmware version for inventory
adb shell getprop gsm.version.baseband
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
