CVE-2026-20460 Overview
CVE-2026-20460 is an information disclosure vulnerability in the MediaTek Modem component caused by improper input validation [CWE-288]. An attacker operating a rogue base station can trigger the flaw when a User Equipment (UE) connects to it, resulting in remote information disclosure. Exploitation requires no additional execution privileges and no user interaction. MediaTek addressed the issue under Patch ID MOLY01811421 and internal Issue ID MSV-6788, disclosed in the July 2026 MediaTek Product Security Bulletin.
Critical Impact
A rogue base station within radio range can extract sensitive modem information from vulnerable UEs without user interaction.
Affected Products
- MediaTek Modem firmware referenced in the July 2026 MediaTek Product Security Bulletin
- Devices integrating affected MediaTek baseband chipsets
- UEs pending vendor firmware updates that include Patch ID MOLY01811421
Discovery Timeline
- 2026-07-01 - CVE-2026-20460 published to NVD
- 2026-07-01 - MediaTek publishes July 2026 Product Security Bulletin containing Patch ID MOLY01811421
- 2026-07-01 - Last updated in NVD database
Technical Details for CVE-2026-20460
Vulnerability Analysis
The vulnerability resides in the MediaTek Modem firmware, which fails to properly validate input received over the cellular radio interface. When a UE attaches to a base station, the modem processes signaling messages from the network. Improper validation of these messages allows an attacker-controlled base station to elicit disclosure of sensitive modem state or memory contents back to the attacker.
Because the flaw is classified under [CWE-288] (Authentication Bypass Using an Alternate Path or Channel), the modem accepts and processes attacker-supplied data through a path that lacks the expected validation controls. The attack surface is the air interface, which explains the Adjacent Network attack vector.
Root Cause
The root cause is improper input validation in modem message handling. The affected code path processes network-originated signaling without sufficient checks on field values or state transitions. This allows crafted messages from a rogue base station to reach code paths that leak information from the modem.
Attack Vector
An attacker must operate a rogue base station and lure a target UE into connecting to it. This typically involves broadcasting with higher signal strength on frequencies the UE monitors, then completing enough of the attach procedure to exchange the malformed messages. Once the UE attaches, the attacker sends crafted signaling that triggers the disclosure. No user interaction is required and no additional privileges are needed on the device.
No public proof-of-concept code has been published. Refer to the MediaTek Security Bulletin July 2026 for technical details from the vendor.
Detection Methods for CVE-2026-20460
Indicators of Compromise
- Unexpected cellular attachment to unknown or unauthorized PLMNs, cell IDs, or TAC values.
- Repeated UE attach or authentication cycles that coincide with abnormal signal-strength conditions in known-safe locations.
- Modem crash logs or diagnostic entries referencing malformed layer-3 signaling.
Detection Strategies
- Correlate mobile device management (MDM) telemetry with baseline PLMN and cell tower data to flag anomalous attachments.
- Monitor for devices reporting downgrade from 5G/LTE to lower-generation radio access when not expected.
- Review vendor security bulletins and firmware inventory to identify devices missing Patch ID MOLY01811421.
Monitoring Recommendations
- Ingest MDM and endpoint telemetry into a centralized analytics platform to detect radio-access anomalies at scale.
- Track firmware and baseband version compliance across the mobile fleet and alert on unpatched devices.
- Establish geofenced baselines for cell-tower connectivity in sensitive sites to flag rogue base station activity.
How to Mitigate CVE-2026-20460
Immediate Actions Required
- Apply the MediaTek Modem firmware update containing Patch ID MOLY01811421 through the device OEM's update channel.
- Inventory all devices with affected MediaTek chipsets and prioritize patch deployment for high-risk users.
- Restrict use of unpatched devices in high-threat environments where rogue base stations are plausible.
Patch Information
MediaTek released the fix in the July 2026 Product Security Bulletin under Patch ID MOLY01811421, Issue ID MSV-6788. Device OEMs must integrate the modem firmware update into their vendor-specific security patches before it reaches end users. Consult the MediaTek Security Bulletin July 2026 for authoritative advisory details.
Workarounds
- Where supported, disable legacy 2G/3G radio access on managed devices to reduce exposure to downgrade-driven rogue base station attacks.
- Enforce policy through MDM to require the latest OEM security patch level on enrolled devices.
- Avoid connecting sensitive devices to cellular networks in locations where rogue base station activity is suspected.
# Example MDM compliance check (pseudocode) for baseband patch level
mdm policy set --name "MediaTek-MOLY01811421" \
--require-security-patch-date "2026-07-01" \
--action "quarantine-if-noncompliant"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
