CVE-2025-26784 Overview
CVE-2025-26784 affects the Non-Access Stratum (NAS) implementation across a broad range of Samsung Exynos Mobile Processors, Wearable Processors, and standalone Modem chipsets. The vulnerability stems from a missing length check that allows an out-of-bounds write [CWE-787] in the baseband firmware processing NAS signaling messages.
An attacker positioned on a mobile network can send malformed NAS traffic to a target device. This can corrupt adjacent memory in the modem, resulting in limited confidentiality and integrity impact on the baseband processor. The flaw is remotely reachable and requires no user interaction or authentication.
Critical Impact
Remote out-of-bounds write in baseband NAS parsing across dozens of Exynos SoCs and modems, exposing smartphones, wearables, and connected devices to memory corruption over the cellular interface.
Affected Products
- Samsung Exynos Mobile Processors: 980, 990, 850, 1080, 2100, 1280, 2200, 1330, 1380, 1480, 2400
- Samsung Exynos Wearable Processors: 9110, W920, W930, W1000
- Samsung Exynos Modems: 5123, 5300 (advisory also references Modem 5400)
Discovery Timeline
- 2025-05-14 - CVE-2025-26784 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-26784
Vulnerability Analysis
The vulnerability resides in the NAS layer of Samsung Exynos baseband firmware. NAS is the 3GPP protocol layer responsible for mobility management, session management, and authentication signaling between a user equipment (UE) and the mobile core network. Because NAS messages are processed by the modem before the application processor, flaws in NAS parsing directly expose the baseband trust boundary.
According to Samsung's advisory, the affected code path fails to validate the length of an attacker-controlled field before writing it into a fixed-size buffer. This produces an out-of-bounds write, classified under [CWE-787]. The condition is reachable over the air via a malicious or rogue base station capable of transmitting crafted NAS Protocol Data Units (PDUs) to the target device.
The scope of affected silicon is unusually wide, covering flagship smartphone SoCs, wearable processors used in Galaxy Watch products, and discrete 4G/5G modems shipped in third-party platforms.
Root Cause
The root cause is missing length validation on an incoming NAS message field. The firmware trusts a length or count value from the network peer and writes past the end of the destination buffer, corrupting adjacent modem memory structures.
Attack Vector
Exploitation requires the attacker to deliver a crafted NAS message to the victim device. This is typically achieved by operating a rogue base station or by relaying malicious signaling on a compromised network segment. No user interaction is required, and the attack executes entirely within the modem context. Refer to the Samsung CVE-2025-26784 Details advisory for vendor-supplied technical context.
Detection Methods for CVE-2025-26784
Indicators of Compromise
- Unexpected modem reboots, radio resets, or repeated cellular disconnections on devices running affected Exynos firmware.
- Presence of unknown or unauthorized base stations (rogue eNodeB/gNodeB) advertising service in the vicinity of targeted users.
- Anomalous NAS signaling patterns, including malformed Attach, Tracking Area Update, or Authentication messages captured by network monitoring.
Detection Strategies
- Monitor mobile device management (MDM) telemetry for baseband firmware versions that predate the Samsung security bulletin fix.
- Correlate cellular anomalies with device location data to identify potential rogue base station activity targeting employees.
- Where lawful and feasible, use radio frequency (RF) monitoring in sensitive facilities to detect unauthorized cellular transmitters.
Monitoring Recommendations
- Track Samsung's product security updates page and align patch SLAs against advisory publication dates.
- Ingest MDM and endpoint telemetry into a centralized analytics platform to identify devices still exposed after patch release.
- Enable crash and diagnostic reporting on managed mobile fleets so modem faults are surfaced rather than silently recovered.
How to Mitigate CVE-2025-26784
Immediate Actions Required
- Apply the Samsung Exynos firmware updates referenced in the vendor advisory as soon as OEM builds become available for each affected device model.
- Inventory all managed handsets, wearables, and IoT devices using affected Exynos SoCs or modems and prioritize patch deployment for high-risk users.
- Instruct high-value targets to disable 2G fallback where supported, reducing exposure to trivial rogue base station downgrade attacks.
Patch Information
Samsung has published fix information in its Semiconductor Product Security Updates portal. Consult the Samsung CVE-2025-26784 Details page for the authoritative list of remediated firmware builds. Device-level patches must be delivered by the OEM integrating the Exynos component, so timelines vary across Samsung Galaxy, Galaxy Watch, and third-party products.
Workarounds
- No documented software workaround exists for the underlying NAS parsing flaw; the fix must be delivered as a modem firmware update by the device vendor.
- Restrict use of untrusted cellular networks in sensitive environments and prefer Wi-Fi with VPN until patched firmware is confirmed installed.
- For enterprise-managed fleets, enforce policies that alert on or block devices running out-of-date baseband builds.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
